Development and Validation of the Eating Disorder Diagnostic Scale

7/27/2019 Development and Validation of the Eating Disorder Diagnostic Scale

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Psychological Assessment Copyright 2000 by the American Psychological Association, Inc.

2000, Vol. 12, No. 2, 123-131 1040-3590/00/ 5.00 DO I: 10.1037//1040-3590.12.2.123

D e v e l o p m e n t a n d V a l i d a t i o n o f t h e E a t i n g D i s o r d e r D i a g n o s t i c S c a l e :

A B r i e f S e l f- R e p o r t M e a s u r e o f A n o r e x ia B u l i m i a

a n d B i n g e -E a t i n g D i s o r d e r

Er i c S t i ce

U n i v e r s i t y o f T e x a s a t A u s t i n

C h r i s ty F T e l c h

S t a n f o r d U n i v e r s i t y

S h i reen L R i zv i

U n i v e r s i t y o f W a s h i n g t o n

This article describes the development and validation of a brief self-report scale for diagnosing anorexia

nervosa, bulimia nervosa, and binge-eating disorder. Study 1 used a panel o f eating-disorder experts and

provided evidence for the content validity of this scale. Study 2 used d ata from fema le participants with

and without eating disorders (N = 36 7) and suggested that the diagnoses from this scale possessed

temporal reliability (m ean K = .80) and criterion v alidity (with interview diagnoses; mean K = .83). In

support o f convergent v alidity, individuals w ith eating disorders identified by this scale showed

elevations on validated measures of eating disturbances. The o verall symptom comp osite also showed

test-retest reliability (r = ,87), internal consistency (mean a = .89), and convergent validity with extant

eating-pathology scales. Results im plied that this scale was reliable and valid in this investigation and that

it may be useful for clinical and research applications.

I t h a s b e e n e s t i m a t e d t h a t 1 0 o f f e m a l e i n d i v i d u a l s i n w e s t e r n

c o u n t r i e s w i l l s u f fe r f r o m a d i a g n o s a b l e e a t i n g d i s o r d e r ( A m e r i c a n

P s y c h i a t r i c A s s o c i a t i o n [ A P A ] , 1 9 9 4 ) , m a k i n g i t o n e o f th e m o r e

p r e v a l en t p s y c h i at r ic p r o b l e m s f a c e d b y w o m e n . A n o r e x i a n e r v o s a

i s c h a r a c t e r i z e d b y ( a ) e x t r e m e e m a c i a t i o n ; ( b ) i n t e n s e f e a r o f

g a i n i n g w e i g h t o r b e c o m i n g f a t d e s p i t e a l o w b o d y w e i g h t ; ( c )

d i s t u r b e d p e r c e p t i o n o f w e i g h t a n d s h a p e , a n u n d u e i n f l u e n c e o f

w e i g h t o r s h a p e o n s e l f - e v a l u a t i o n , o r a d e n i a l o f t h e s e r i o u s n e s s

o f t h e l o w b o d y w e i g h t ; a n d ( d ) a m e n o r r h e a ( A P A , 1 9 9 4 ). T h i s

d i s o r d e r h a s a l i f e t i m e p r e v a l e n c e o f a l m o s t 1 a m o n g f e m a l e s , i s

r e f r a c t o r y t o t r e at m e n t , s h o w s a c h r o n i c c o u r s e , r e s u l t s i n s e r i o u s

m e d i c a l c o m p l i c a t i o n s , a n d i s a s s o c i a t e d w i t h p s y c h i a t r i c c o m o r -

b i d i t y s u c h a s m o o d , a n x i e t y , a n d p e r s o n a l i t y d i s o r d e r s ( W i l s o n ,

H e f f e r n a n , & B l a c k , 1 9 9 6 ) .

B u l i m i a n e r v o s a i n v o l v e s ( a ) r e c u r r e n t e p i s o d e s o f u n c o n t r o l l a -

b l e c o n s u m p t i o n o f l a rg e a m o u n t s o f f o o d , ( b ) c o m p e n s a to r y

Eric Stice, Department of Psychology, University o f Texas at Austin;

Christy F. Telch, Dep a~n ent of Psychiatry and Behavioral Sciences,

Stanford University; Sh ireen L. Rizv i, Department o f Psychology, U niver -

sity of Washington.

This study was supported by Postdoctoral Fellowship MH19908, Career

Award MH01708, Exploratory Development Grant MH54641, and Re-

search Grant MH50271 from the National Institute of Mental Health, as

well as by a grant f rom the McK night Foundation. W e thank K im Frornme,

Helen C. Kraemer, H eather Shaw, and M ichael J. Telch for their thoughtful

input regarding this article.

Correspondence concerning this article should be addressed to Eric

Stice, Department of Psychology, 330 Mezes Hall, University of Texas

at Austin, Austin, Texas 78712. Electronic m all may be sent to stice@psy.

utexas.edu.

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b e h a v i o r t o p r e v e n t c o n s e q u e n t w e i g h t g a i n ( e . g . , v o m i t i n g , l a x a -

t i v e a b u s e , d i u r e t i c a b u s e , o r e x c e s s i v e e x e r c i s e ) , a n d ( c ) u n d u e

i n f l u e n c e o f w e i g h t a n d s h a p e o n s e l f - e v a l u a t i o n ( A P A , 1 9 9 4 ) . T h e

l i f e t i m e p r e v a l e n c e f o r b u l i m i a n e r v o s a i s a p p r o x i m a t e l y 2 f o r

f e m a l e s ( N e w m a n e t a i . , 1 9 9 6 ; W h i t a k e r e t a l ., 1 9 9 0 ) . T h i s d i s o r -

d e r i s m a r k e d b y a p e r s i s t e n t c o u r s e a n d i s a s s o c i a t e d w i t h h i g h

l e v e l s o f c o m o r b i d p s y c h o p a t h o l o g y , i n c l u d i n g a f f e c t i v e d is o r d e r s ,

a nxie ty d i sorde r s , a nd subs ta nc e a buse (Ga r f inke l e t a l . , 1995;

K e l l e r , H e r z o g , L a v o r i , B r a d b u r n , & M a h o n e y , 1 9 9 2 ) .

B i n g e - e a t i n g d i s o r d e r i n v o l v e s ( a ) r e p e a t e d e p i s o d e s o f u n c o n -

t r o l l a b l e b i n g e e a t i n g c h a r a c t e r i z e d b y c e r t a i n f e a t u r e s ( e .g . , r a p i d

e a t i n g o r e a ti n g a l o n e b e c a u s e o f e m b a r r a s s m e n t ) , ( b ) m a r k e d

d i s t r es s r e g a r d i n g b i n g e e a t i n g , a n d ( c ) t h e a b s e n c e o f c o m p e n s a -

t o r y b e h a v i o r s ( A P A , 1 9 9 4 ) . T h e l i f e t i m e p r e v a l e n c e f o r b i n g e -

e a t i n g d i s o r d e r i s a p p r o x i m a t e l y 4 i n t h e c o m m u n i t y ( S p i t z e r e t

a l ., 1 9 9 3 ) , b u t i t h a s b e e n e s t i m a t e d th a t a b o u t 3 0 o f in d i v i d u a l s

p r e s e n t i n g f o r w e i g h t - c o n t r o l t r e a t m e n t m e e t c r i t e r i a f o r t h i s d i s -

o r d e r ( B r o d y , W a l s h , & D e v l i n , 1 9 9 4 ) . T h i s d i s o r d e r a p p e a r s t o

h a v e a p e r s i s t e n t c o u r s e a n d i s a s s o c i a t e d w i t h o b e s i t y , w e i g h t

c y c l i n g , h e a l t h c o m p l i c a t i o n s , a n d p s y c h i a t r i c c o m o r b i d i t y ( W i l -

son e t a l . , 1996; Te lc h & St ic e , 1998) .

R e s e a r c h o n t h e e t i o l o g y , p r e v e n t i o n , a n d t r e a t m e n t o f ea t i n g

d i s o r d e r s h a s i n c r e a s e d d r a m a t i c a l l y o v e r th e p a s t 2 d e c a d e s ( S m o -

l a k , L e v i n e , & S t r i e g e l - M o o r e , 1 9 9 6 ) , b u t p r o g r e s s h a s b e e n l i m -

i t e d i n p a r t b y t h e s c a r c i t y o f v a l i d a t e d m e a s u r e s o f e a t i n g d i s o r -

d e r s . A l t h o u g h t h e r e a r e s t r u c t u r e d p s y c h i a t r i c i n t e r v i e w s f o r

a r r i v i n g a t

Diagnos t ic and S ta t i s t i ca l Man ual o f Men ta l Disorders

(4 th e d . ;

DSM-1V,

A P A , 1 9 9 4 ) d i a g n o s e s o f a n o r e x i a n e r v o s a ,

b u l i m i a n e r v o s a , a n d b i n g e - e a t i n g d i s o r d e r ( e . g . , t h e E a t i n g D i s -

o r d e r E x a m i n a t i o n [ E D E ; F a i r b u r n & C o o p e r , 1 9 9 3 ] a n d t h e

S t r u c t u r e d C l i n i c a l I n t e r v i e w f o r D S M [ S C I D ; S p i t z e r , W i l l i a m s ,


2/9

1 2 4 STIC E, TELC H , A N D R IZV I

G i b b o n , & F i r s t , 1 9 9 0 ] ) , n o p a r a l l e l s e l f - r e p o r t q u e s t i o n n a i r e m e a -

s u r e e x i s t s . A v a i l a b l e s e l f - r e p o r t q u e s t i o n n a i r e s , s u c h a s t h e B u -

l i m i a T e s t - - R e v i s e d ( T h e l e n , F a r m e r , W o n d e r l i c h , & S m i t h ,

1 9 9 1 ), Q u e s t i o n n a i r e o n E a t i n g a n d W e i g h t P a t t e r n s ( S p i t z e r e t a l. ,

1 9 9 2 ) , E a t i n g D i s o r d e r E x a m i n a t i o n - - - Q u e s t i o n n a i r e ( F a i r b u r n &

B e g l i n , 1 9 9 4 ) , a n d Q u e s t i o n n a i r e f o r E a t i n g D i s o r d e r D i a g n o s e s

( M i n t z , O ' H a U o r a n , M u l h o l l a n d , & S c h n e i d e r , 1 9 9 7) , d o n o t y ie l d

DSM-IV

d i a g n o s e s f o r a l l t h r e e e a t i n g d i s o r d e r s . M o r e o v e r , t h e

r e l i a b i l i t y a n d v a l i d i t y o f m e a s u r e s f r o m e x t a n t s e l f - r e p o r t q u e s -

t i o n n a i r e s h a v e n o t b e e n w e l l e s t ab l i s h e d . F o r e x a m p l e , w e w e r e

u n a b l e t o l o c a t e a n y p u b l i s h e d s t u d i e s t h a t r e p o r t t h e t e s t - r e t e s t

r e l i a b i l i t y f o r DSM-IV e a t i n g - d i s o r d e r d i a g n o s e s g e n e r a t e d b y

t h e s e s e l f - r e p o r t q u e s t i o n n a i r e s . S i m i l a r l y , t h e r e a p p e a r t o b e n o

p u b l i s h e d s t u d i e s t h a t r e p o r t t h e a g r e e m e n t b e t w e e n DSM-IV

e a t i n g - d i s o r d e r d i a g n o s e s a s c e r t a i n e d t h r o u g h v a l i d a t e d s t r u c t u r e d

i n t e r v i e w s a n d t h o s e g e n e r a t e d b y t h e s e s e l f - re p o r t q u e s t i on n a i r e s .

A b r i e f s e l f - r ep o r t q u e s t i o n n a i r e w o u l d b e v e r y u s e f u l f o r e t i o -

l o g i c r e s e a r c h , i n t h a t i t i s t i m e c o n s u m i n g a n d e x p e n s i v e t o

c o n d u c t l e n g t h y s t r u c t u r ed p s y c h i a t r i c i n te r v i e w s w i t h l a r g e n u m -

b e r s o f p a r t i c i p a n t s . S u c h a q u e s t i o n n a i r e m i g h t a l s o b e u s e f u l

w h e n r e s e a r c h e r s n e e d r e l a t i v e l y f r e q u e n t m e a s u r e m e n t o f e a t i n g

p a t h o l o g y ( e .g . , p r e v e n t i o n p r o g r a m s o r t r e a t m e n t s t u d i es ) , a s i t

w o u l d m i n i m i z e t h e r e s p o n s e b u r d e n f o r p a r ti c i p a n ts . F i n a l ly , s u c h

a m e a s u r e m i g h t p r o v e u s e f u l i n c l i n i c a l s e t t i n g s ( e . g . , p r i m a r y c a r e

o f f i c e s ) w h e r e a b r i e f q u e s t i o n n a i r e i s d e s i r e d t o i d e n t i f y i n d i v i d -

u a l s w i t h e a t i n g p a t h o l o g y .

A c c o r d i n g l y , w e s o u g h t t o d e v e l o p a b r i e f s e lf - r e p o r t s c al e t h a t

w o u l d p r o v i d e d i a g n o s e s o f a n o r e x i a n e r v o s a , b u l i m i a n e r v o s a ,

a n d b i n g e - e a t i n g d i s o r d e r , a n d t o g e n e r a t e e v i d e n c e o f t h e r e l i a b il -

i t y a n d v a l i d i t y o f t h is n e w d i a g n o s t i c i n s t ru m e n t . S t u d y 1 de -

s c r i b e s t h e p r o c e s s e s b y w h i c h w e g e n e r a t e d i t e m s a n d e x a m i n e d

t h e c o n t e n t v a l i d i t y o f t h i s n e w s c a l e . S t u d y 2 a s s e s s e s t h e t e s t -

r e t e s t r e l i a b i l i t y , c r i t e r i o n v a l i d i t y , a n d c o n v e r g e n t v a l i d i t y o f t h i s

d i a g n o s t ic s c a l e . A s s o m e r e s e a r c h e r s m a y b e i n t e r e s te d i n u s i n g

a n o v e r a l l e a t i n g - d i s o r d e r s y m p t o m c o m p o s i t e f o r e t i o l o g i c , p r e -

v e n t i o n , o r t r e a t m e n t s t u d i es ( b e c a u s e o f t h e l o w b a s e r a t e o f t h e s e

d i s o r d e rs ) , a t e r t i ar y a i m w a s t o e x p l o r e t h e p s y c h o m e t r i c p r o p e r -

t i e s o f s u c h a s y m p t o m c o m p o s i t e d e r i v e d f r o m t h i s d i a g n o s t i c

s c a l e . I n p a r t i c u l a r , t h e t e s t - r e t e s t r e l i a b i l it y , i n t e r n a l c o n s i s t e n c y ,

a n d c o n v e r g e n t v a l i d i t y o f t h e o v e r a l l s y m p t o m c o m p o s i t e w e r e

e x a m i n e d .

S t u d y 1

Overview

T h e p u r p o s e o f S t u d y 1 w a s t o ( a ) g e n e r a t e a s e t o f it e m s t o

a s s e s s t h e DSM-IV d i a g n o s t i c c r i t e r i a f o r a n o r e x i a n e r v o s a ,

b u l i m i a n e r v o s a , a n d b i n g e - e a t i n g d i s o r d e r f o r a n E a t i n g D i s -

o r d e r D i a g n o s t i c S c a l e ( E D D S ) , ( b ) d o c u m e n t t h a t al l r e l e v a n t

s y m p t o m s w e r e i n c l u d e d a n d t h a t n o i r r e l e v a n t o n e s w e r e

i n c l u d e d , a n d ( c ) r e f in e i t e m c o n t e n t a n d i n s t r u ct i o n s . F o l l o w -

i n g r e c o m m e n d a t i o n s r e g a r d i n g c o n t e n t v a l i d a ti o n ( H a y n e s ,

R i c h a r d , & K u b a n y , 1 9 9 5 ) , w e u s e d a m u l t i s t e p p r o c e s s t o

a c c o m p l i s h t h e s e a i m s .

Method

Step 1

I tems we re derived from mul t ip le sources to enhance the conten t va l id i ty

of the sca le . I tems assessing DSM-IV diagnost ic cr i te r ia for anorex ia

nervosa , bu l imia nervosa , and b inge-eat ing d isorder were adapted from

validated smactured psychiatric interviews, which assessed these disorders:

the EDE (Fai rburn & Cooper, 1993) and the ea t ing-d isorder modu le of the

SCID (Spi tzer e t a l. , 1990). W e used the version of the EDE that assesses

d iagnost ic cr i te r ia for anorex ia nervosa , bu l imia nervosa , and b inge-eat ing

disorder. We a lso consul ted the DSM-1V APA, 1994) regard ing d iagnost ic

cri ter ia for these th ree ea t ing d isorders in an effort to ensure tha t a l l

re levant symptoms were represen ted on the sca le . I tems were worded to

capture d iagnost ic cr i te r ia for these d isorders , inc lud ing the necessary t ime

windows for various behaviors .

Step

To document tha t a l l o f the d iagnost ic cr i te r ia for the th ree ea t ing

disorders were inc luded and tha t no i rre levant in forma t ion was inc luded in

the EDDS, a panel o f ea t ing-d isorders researchers from aroun d the count ry

evaluated a pre l im inary version of th i s quest ionnaire . Twenty-six ea t ing-

d isorder expert s , iden t i f ied th rough a l i te ra ture search , were mai led the

pre l iminary draft o f the ED DS, a l i s t o f the d iagnost ic cr i te r ia taken d i rec tly

f ro m t h e DSM-IV and a cover le t ter wi th instructions. Experts were asked

to (a) check tha t a l l o f the DSM-IV diagnost ic cr i te r ia were assessed on

EDDS, (b) cross ou t any EDDS i tems that d id no t reflec t a DSM-IV

symptom, (c) suggest ref inem ents to the w ord ing of i tems or inst ruct ions,

and (d) w ri te down any ad di t ional i tems that should be inc luded . O f the 26

part ic ipants who were mai led th is in format ion , 14 (54%) re turned com-

pleted packets. F our of the 14 experts n oted that one diagnostic cr iteria was

not reflec ted on the EDDS (fast ing) and made suggest ions regard ing

wording of th is i tem. Experts agreed tha t a l l rem ain ing d iagnostic cr i te r ia

were inc luded and tha t no i rre levant i tems were inc luded . Experts a l so

provided severa l usefu l suggest ions tha t c larif ied the word ing of i tems an d

inst ruct ions. These respon ses were used to gu ide a rev is ion of the pre l im-

inary EDDS.

Step 3

The rev ised draft o f EDDS was p i lo t tes ted wi th pat ien ts from an

eat ing-d isorders cl in ic , underg raduate s tudents , a nd h igh school s tudents

(N = 15). These part ic ipants were asked to comm ent on the c larity of the

quest ions and instructions. This feedback w as used to g u ide a f ina l rev is ion

of the pre l iminary EDDS, which primari ly cen tered on c lari fy ing the

instructions.

Results

T h e a b o v e i t e m - g e n e r a t i o n a n d r e f i n e m e n t p r o c e d u r e s r e s u l te d

i n a 2 2 - i t e m v e r s i o n o f t h e E D D S . I t e m s u s e d a c o m b i n a t i o n o f

L i k e n , y e s - n o , f r e q u e n c y , a n d w r i t e - i n r e s p o n s e f o r m a t s t o a s s e s s

a l l o f t h e DSM-IV d i a g n o s t i c s y m p t o m s f o r a n o r e x i a n e r v o s a ,

b u l i m i a n e r v o s a , a n d b i n g e - e a t i n g d i s o r d e r. I n a n e f f o r t t o m i n i -

m i z e t h e e f f e c t s o f i d i o s y n c r a t ic c o n c e p t i o n s o f w h a t c o n s t it u t e s a

b i n g e , w e d i d n o t u s e t h i s t e r m i n t h e s c a le . T h e E D D S i s

i n c l u d e d i n t h e A p p e n d i x e s , a l o n g w i t h t h e s c o r i n g a l g o r i t h m ' .

S t u d y 2

Overview

T h e p u r p o s e o f S t u d y 2 w a s t o e x a m i n e t h e t e s t - r e t e s t re l i a bi l -

i t y , c r i t e r i o n v a l i d it y , a n d c o n v e r g e n t v a l i d i ty o f th e E D D S e a t i n g -

d i s o r d e r d i a g n o s e s , a s w e l l a s t h e t e s t - r e t e s t r e l i a b i l i t y , i n t e r n a l

c o n s i s t e n c y , a n d c o n v e r g e n t v a l i d i t y o f t h e E D D S s y m p t o m

c o m p o s i t e .


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E A T I N G D I S O R D E R D I A G N O S T I C S C A L E 25

M e t h o d

P a r t i c i p a n t s

A n e f f o r t w a s m a d e t o r e c r u it a h e t e r o g e n e o u s s a m p l e t h a t w a s d i v e r s e

i n a g e , s o c i o e c o n o m i c s t a t u s, a n d g e o g r a p h i c l o c a t io n t o m a x i m i z e t h e

g e n e r a l i z a b i l i t y o f t h e f i n d i n g s . Pa r t i c i p a n t s w e r e 3 6 7 f e m a l e s b e t w e e n t h e

a g e s o f 1 3 a n d 6 5 r e c r u i t e d f r o m t h e m e t r o p o l it a n a r e a s o f S a n F r a n c i s c o ,

N e w Y o r k , M i n n e a p o l i s - S t . Pa u l , a n d A u s t i n . Pa r t i c i p a n t s w e r e r e c r u i t e d

f r o m s e v e r a l o n g o i n g p r o j e c t s , i n c l u d i n g ( a ) a r a n d o m i z e d c l i n i c a l t r i a l f o r

t h e t r e a t m e n t o f a n o r e x i a n e r v o s a ( n = 1 2 ), ( b ) a r a n d o m i z e d c l in i c a l t ri a l

f o r t h e t r e a t m e n t o f b u l i m i a n e r v o s a ( n = 3 ) , ( c) a r a n d o m i z e d c l i n i c a l t r i a l

f o r t h e t r e a t m e n t o f b i n g e - e a t i n g d i s o r d e r ( n = 1 7 ) , ( d ) a m u l t i s i t e s t u d y o n

t h e l o n g i t u d i n a l c o u r s e o f t h r e s h o l d a n d s u b t h r e s h o l d e a t i n g d i s o r d e r s i n a

n o n - t r e a t m e n t s e e k i n g s a m p l e ( n = 1 8 5 ) , ( e ) a m u l t i s i t e s t u d y o n a f f e c t

( n = 3 8 ) , ( f ) a l o n g i t u d i n a l s t u d y o f t h e r i s k f a c t o r s f o r e a t i n g d i s o r d e r s

( n = 1 0 9 ) , a n d ( g ) a n i n p a t i e n t p s y c h i a t r i c t r e a t m e n t u n i t ( n = 3 ).

Pa r t i c i p a n t s f r o m t h e f i r s t s i x s o u r c e s w e r e r e c r u i t e d d i r e c t l y f r o m t h e

c o m m u n i t y t h r o u g h a d v e r t i s e m e n t s p l a c e d i n l o c al m e d i a , f l i e r s d i st r i bu t e d

a t u n i v e r s i t i e s a n d m e d i c a l c l i n i c s , a n d d i r e c t m a i l i n g s t o e l i g i b l e f e m a l e s

b e t w e e n t h e a g e s o f 1 3 a n d 6 5 t o p a r t i c i p a te i n t h e s e r e s e a r c h s t u d i e s . T h e 3

p a t i e n t s r e c r u i t e d f r o m t h e i n p a t i e n t t r e a t m e n t u n i t w e r e a p p r o a c h e d d i -

r e c t ly b e c a u s e a c h a r t r e v i e w s u g g e s t e d th a t t h e y h a d a d i a g n o s i s o f

a n o r e x i a n e r v o s a . D a t a f o r t h i s s t u d y w e r e c o l l e c t e d a t : ( a ) v a r i o u s a s s e s s -

m e n t p o i n t s i n t h e t h r e e r a n d o m i z e d c l i n i c a l t r i a l s a n d t h e l o n g i t u d i n a l

c o u r s e s t u d y , ( b ) a t t h e b a s e l i n e a s s e s s m e n t o f t h e a f f e c t s t u d y a n d t h e

l o n g i t u d i n a l r i s k f a c t o r s t u d y , a n d ( c ) w i t h i n t h e f i r s t m o n t h o f t r e a t m e n t f o r

t h e 3 a n o r e x i c i n d i v i d u a l s f r o m t h e i n p a t i e n t t r e a t m e n t u n i t .

Pa r t i c i p a n t s r a n g e d i n a g e f r o m 1 3 t o 6 1 ( M = 2 9 .7 ,

SD

= 1 3 .2 ). T h e

s a m p l e w a s c o m p o s e d o f p a r ti c i p a nt s w h o w e r e 2 % A s i a n o r P a c i f ic

I s l a n d e r , 2 % B l a c k , 6 % H i s p a n i c , 1 % N a t i v e A m e r i c a n , 8 0 % C a u c a s i a n ,

a n d 9 % w h o s p e c i f i e d o t h e r o r m i x e d - r a c i a l h e r i t a g e . E d u c a t i o n a l a t -

t a i n m e n t r a n g e d f r o m s o m e h i g h s c h o o l ( 2 2 % ) t o g r a d u a t e o r p r o f e s s io n a l

d e g r e e ( 1 7 % ) , w i t h a m o d e o f s o m e c o l l e g e e d u c a t io n ( 2 9 % ) .

M e a s u r e s

S tructured Psychia tr ic In terv iew. T h e E D E ( F a i r bu r n & C o o p e r , 1 9 9 3)

w a s t h e p r i m a r y g o l d s t a n d a r d a g a i n s t w h i c h o u r n e w s e l f- r e p o rt di a g -

n o s t ic s c a l e w a s c o m p a r e d f o r v a l i d a ti o n p u r p o s e s . T h e E D E i s a s t r u c t u re d

p s y c h i a t r i c i n t e r v i e w t h a t a s s e s s e s d i a g n o s t i c c r i t e r i a f o r D S M I V e a t i n g

d i s or d e r s. W e u s e d t h e v e r s i o n t h a t a s s e s s e s d i a g n o s t i c c r it e r ia f o r a n o r e x i a

n e r v o s a , b u l i m i a n e r v o s a , a n d b i n g e - e a t in g d i s or d e r . T h e E D E a l s o c o n -

t a i n s f o u r s u b s c a l e s t h a t m e a s u r e d i e t a r y r e s t r a in t , e a t i n g c o n c e r n , w e i g h t

c o n c e r n , a n d s h a p e c o n c e r n . U s i n g c o m m u n i t y a n d c l in i c a l s a m p l e s , s tu d -

i e s b y Co o p e r , Co o p e r , a n d Fa i r b u r n ( 1 9 8 9 ) , Fa i r b u r n a n d Co o p e r ( 1 9 9 3 ) ,

R i z v i , P e te r s o n , C r o w , a n d A g r a s ( 1 9 99 ) , W i l l i a m s o n , A n d e r s o n , J a c k m a n ,

a n d J a c k s o n ( 1 9 9 5 ) , a n d W i l s o n a n d Sm i t h ( 1 9 8 9 ) r e p o r t e d i n t e r n a l c o n -

s i s t e n c y c o e f f i c i e n t s f o r t h e E D E s c a l e s r a n g i n g f r o m .7 6 to . 9 0 , t e s t - r e t e s t

r e l i a b i l i t y c o r r e l a t i o n s f o r d i a g n o s t i c i t e m s r a n g i n g f r o m .8 3 t o . 9 7 , a n d

i n t e r r a t e r r e l i a b i l i t y k a p p a s r a n g i n g f r o m .8 3 t o . 9 9 .

T o a s s e s s t h e i n t e r r a t e r r e li a b i li t y o f t h e E D E i n t h i s s t u d y , a s u b s e t

( 2 5 % ) o f E D E i n t e r v ie w s w e r e a u d i o t a p e d a n d r a te d b y a s e c o n d i n t e r -

v i e w e r w h o w a s u n a w a r e o f t h e o r i g i n a l d i a g n o si s , r e s u lt i n g i n a c c e p ta b l e

i n t e r r a t e r a g r e e m e n t ( k a p p a s r a n g e d f r o m .9 2 to 1 .0 0) . T h e E D E w a s

a d m i n i s t e r e d t o 3 4 6 o f t h e 3 6 7 p a r t i c i p a n t s t o a s c e r t a i n e a t i n g - d i s o r d e r

d i a g n o s i s .

T h e SCI D ( Sp i t z e r e t a l . , 1 9 9 0 ) s e r v e d a s t h e g o l d s t a n d a r d a g a i n s t

w h i c h o u r s e l f -r e p o r t d ia g n o s t i c s c a le w a s c o m p a r e d f o r a s u b s e t o f

p a r t i c i p a n t s ( t h e 3 a n o r e x i a n e r v o s a p a t i e n t s f r o m t h e i n p a t i e n t u n i t a n d 1 8

p a r t ic i p a n ts f r o m t h e a f f e c t s t u d y ) w h e r e w e c o u l d n o t a d m i n i s t e r t h e m o r e

d e t a i l e d E D E . T h e SCI D i s a s ta n d a r d i z e d i n t e r v i e w t h a t a s s e s s e s p s y c h i -

a t r i c s t a t u s f o r m a j o r A x i s I p s y c h i a t r i c d is o r d e r s . Re s e a r c h h a s p r o v i d e d

e v i d e n c e o f t h e r e l i a b il i t y d i a g n o s e s o f t h e SCI D , w i t h i n t e r r a te r r e l i a b il i t y

a g r e e m e n t k a p p a s r a n g i n g f r o m .7 0 t o 1 .0 0 a n d t e s t - r e t e s t r e l i a b i li t y o f th e

e a t i n g - d i s o r d e r s s e c t i o n s r a n g i n g f r o m .8 2 t o . 9 0 i n c o m m u n i t y a n d c l i n i c a l

s a m p l e s ( P ik e , L o e b , & W a l s h , 1 9 9 5 ; Se g a l , H e r s e n , & V a n H a s s e l t , 1 9 9 4 ;

S t u k e n b e r g , D u r a , & K i e c o l t - G l a s e r , 1 9 9 0 ) .

R e s p o n s e s to t h e E D E a n d S C I D i n t e r v ie w s w e r e u s e d t o g r o u p p a r t ic -

i p a n t s i n t o f o u r d i a g n o s t i c c a t e g o r i e s :

D S M I V a n o r e x i a

n e r v o s a ( n = 1 5 ) ,

D S M I V b u l i m i a n e r v o s a ( n = 3 1 ) , D S M I V b i n g e - e a t i n g d i s o r d e r ( n =

4 8 ) , a n d n o n e a t i n g d i s o r d e r e d c o n t r o l s (n = 2 7 3 ) .

Yale Brow n Corn el l Eat ing Disorder Scale . T h e Y a l e - B r o w n -

C o r n e l l E a t i n g D i s o r d e r S c a l e ( Y B C - E D S ; M a z u r e , H a l m i , S u n d a y , R o -

m a n o , & E i n h o r n , 1 9 9 4 ) i s a n 8 4 - i t e m s t r u c t u r e d i n t e r v i e w t h a t a s s e s s e s

o b s e s s i o n s a n d r i tu a l s r e l a t in g t o f o o d , e a t i n g , w e i g h t , a n d s h a p e i s s u e s .

R e s e a r c h h a s s u p p o r t e d t h e r e l i ab i li ty o f t h e Y B C - E D S m e a s u r e s , w i t h

i n t e r n a l c o n s i s t e n c y c o e f f i c i e n t s r a n g i n g f r o m .8 2 to . 9 0 a n d i n t e r r a t e r

a g r e e m e n t k a p p a s r a n g i n g f r o m . 8 0 t o 1 . 0 0 i n c l i ni c a l s a m p l e s ( M a z u r e e t

a l . , 1 9 9 4 ; Su n d a y , H a l m i , & E i n h o r n , 1 9 9 5 ) . A l l p a r t i c i p a n t s c o m p l e t e d t h e

Y B C- E D S e x c e p t th e 3 8 p a r t i c i p a n t s f r o m t h e a f f e c t s t u d y , 1 0 9 p a r t ic i p a n t s

f r o m t h e l o n g i t u d i n a l r is k f a c t o r s t u d y , a n d t h e 3 a n o r e x i c p a r t i c i p a n t s f r o m

t h e i n p a t i e n t t r e a t m e n t u n i t .

Three Factor Eating Questionnaire. T h e T h r e e - F a c t o r E a t i n g Q u e s -

t i o n n a i r e ( T FE Q ; S t u n k a r d & M e s s i c k , 1 9 8 5 ) i s a 5 4 - i t e m q u e s t i o n n a i r e

w i t h t h r e e s u b s c a l e s m e a s u r i n g c o g n i t i v e ( d i e ta r y ) r e s t r a i n t, p e r c e i v e d

h u n g e r , a n d e m o t i o n a l l y b a s e d d i s i n h i b i t i o n o f e a t i n g . T h e r e l i a b i l i t y a n d

v a l id i ty o f t h e T F E Q s u b s c a l e s h a s b e e n s u p p o r t e d b y r e s e a r c h i n d ic a t i n g

t h a t t h e in t e r n a l c o n s i s t e n c y c o e f f i c i e n t s r a n g e d b e t w e e n . 8 5 a n d . 9 3 , a n d

t h a t t h e s u b s c a l e s c o r r e l a t e d w i t h d i e t a r y in t a k e a n d d i s c r i m i n a t e d b e t w e e n

d i e te r s a n d n o n d i e t e r s i n b o t h c o m m u n i t y a n d c l in i c a l s a m p l e s ( F r e n c h ,

J e f f e r y , & W i n g , 1 9 9 4 ; L a e s s l e , T u s c h l , K o t t h a u s , & P i r k e , 1 9 8 9 ; S t u n k a r d

& M e s s i c k , 1 9 8 5 ) . T h e 3 8 p a r t i c i p a n t s f r o m t h e a f f e c t s t u d y , 1 0 9 p a r t i c i -

p a n t s f r o m t h e l o n g i t u d i n a l r i s k - f a c t o r s t u d y , a n d t h e 3 a n o r e x i c p a r t i c i -

p a n t s f r o m t h e i n p a t ie n t u n i t d i d n o t c o m p l e t e t h e T F E Q .

Eat ing D isorder Diagnost ic Scale . I t e m s a s s e s s i n g t h e D S M I V d i a g -

n o s t i c c r i t e r i a f o r a n o r e x i a n e r v o s a , b u l i m i a n e r v o s a , a n d b i n g e - e a t i n g

d i s o r d e r w e r e d e v e l o p e d a n d r e v i s e d f o l l o w i n g t h e p r o c e d u r e s d e s c r i b e d i n

S t u d y 1 . R e s p o n s e s to t h e E D D S w e r e u s e d t o g r o u p p a r t i c i pa n t s i n to f o u r

d i a g n o s t i c c a t e g o r i e s : D S M I V a n o r e x i a n e r v o s a ( n = 1 8 ) , D S M I V b u -

l i m i a n e r v o s a ( n = 3 9 ) ,

D S M I V

b i n g e - e a t i n g d i s o r d e r ( n = 5 7 ) , a n d

n o n e a t i n g d i so r d e r e d ( n = 2 5 3 ). A s n o t e d a b o v e , b e c a u s e s o m e r e s e a r c h e rs

m a y d e s i r e a b r o a d b a n d m e a s u r e o f e a t in g p a t h o l og y , a n o v e r a l l s y m p t o m

c o m p o s i t e w a s f o r m e d b y s t a n d a r d i z i n g a l l i t e m s ( t o c o n t r o l f o r t h e e f f e c t s

o f t h e d i f f e r e n t re s p o n s e f o r m a t s ) a n d t h e n s u m m i n g a c r o s s a l l i te m s

( e x c e p t t h e h e i g h t a n d b i r t h c o n t r o l p i ll i t e m s ) . T h u s , t h e s y m p t o m c o m -

p o s i t e r e f l e c t e d e a c h p a r t i c i p a n t ' s o v e r a l l l e v e l o f e a t i n g p a t h o l o g y .

P r o c e d u r e s

A t b a s e l i n e , a l l p a r t i c i p a n t s c o m p l e t e d t h e E D D S p r i o r t o p a r t a k i n g i n

t h e s t r u c t u r e d d i a g n o s t i c i n t e r v i e w ( e i t h e r t h e E D E o r t h e SCI D ) . T h i s

o r d e r w a s c h o s e n b e c a u s e c o n c e p t s s u c h a s b i n g e e a t in g e p i so d e s a r e

d e f i n e d i n t h e i n t e r v i e w , a n d w e w a n t e d t o m i n i m i z e t h e p o s s i b i l i t y t h a t

c o m p l e t i n g t h e i n t e r v i e w w o u l d i n f l u e n c e h o w p a r t ic i p a n ts r e s p o n d e d t o

t h e E D D S . A l l i n t e r v ie w s w e r e c o n d u c t e d b y c l in i c a l a s s e s s o r s w i t h e i t h e r

a b a c h e l o r ' s , m a s t e r ' s , o r d o c t o ra t e i n p s y c h o l o g y . C l i n i c a l a s s e s s o r s

a t t e n d e d 1 6 h r o f t r a i n i n g , w h e r e i n s t r u c t u r e d i n t e r v i e w s k i l l s w e r e t a u g h t ,

d i a g n o s t i c c r i t e r ia f o r e a t i n g d i s o r d e r s w e r e r e v i e w e d , s i m u l a t e d i n t e r v i e w s

w e r e o b s e r v e d , a n d i n t e r v i e w s w e r e r o l e p l a y e d . A s s e s s o r s h a d t o d e m o n -

s t r a t e a n i n t e r r a t e r a g r e e m e n t (K > . 8 0 ) w i t h e x p e r t s w i t h t a p e - r e c o r d e d

i n t e r v i e w s b e f o r e t h e y w e r e a l l o w e d t o c o l l e c t d a t a . A f t e r t h e i n t e r v i e w ,

c l i n i c a l a s s e s s o r s m e a s u r e d h e i g h t a n d w e i g h t . Pa r t i c i p a n t s f r o m t h e f i r s t

f o u r e a t i n g -d i s o r d e r st u d i e s t h e n c o m p l e t e d t h e T F E Q a n d t h e Y B C - E D S .

A r a n d o m l y s e l e c t e d s u b s e t o f p ar t ic i p a n ts ( N = 5 5 ) f r o m t h e l o n g i t u d in a l

c o u r s e o f e a t in g d i s o r d e rs s t u d y w a s a s k e d t o c o m p l e t e t h e E D D S 1 w e e k

a f t e r c o m i n g i n t o t h e l a b o r a t o r y f o r t h e i r s t r u c t u r e d i n t e r v i e w t o p r o v i d e

d a t a o n t h e t e s t - r e t e s t r e l i a b i l i t y o f t h i s s c a l e . Pa r t i c i p a n t s w e r e c o m p e n -

s a t e d f o r c o m p l e t i n g th e s e m e a s u r e s ( c o m p e n s a t i o n r a n g e d f r o m $ 1 5 t o

$ 5 0 , d e p e n d i n g o n t h e s t u d y ) .


4/9

126 STICE, TELCH, AND RIZVI

R e s u l t s

O b s e r v e d m e a n s a n d s t a n d a r d d e v i a t i o n s f o r a l l c o n t i n u o u s

m e a s u r e s u s e d i n S t u d y 2 a r e r e p o r t e d i n T a b l e 1 .

T e s t - R e t e s t R e l i a b i l i ty

T h e 1 - w e e k t e s t - r e t e s t k a p p a c o e f f i c i e n t w a s . 9 5 f o r a n o r e x i a

n e r v o s a d i a g n o s e s , a n d t h e o v e r a l l a c c u r a c y r a t e w a s . 9 8 . K a p p a

r e p r e s e n t s a c h a n c e - c o r r e c t e d l e v e l o f a g r e e m e n t b e t w e e n t w o

n o m i n a l v a r i a b l e s , w h i c h , i n t h i s c a s e , w e r e t h e E D D S d i a g n o s e s

a t T i m e 1 a n d T i m e 2 . A c c u r a c y i s th e p r o p o r t i o n o f i n d i v i d u a l s i n

t h e s a m p l e t h a t w e r e l a b e l e d a s d i s o r d e r e d o r n o n d i s o r d e r e d b y t h e

E D D S a t b o t h T i m e 1 a n d T i m e 2 . T h e 1 - w e e k te s t - re t e s t k a p p a

c o e f f i c i e n t w a s . 7 1 f o r b u l i m i a n e r v o s a d i a g n o s e s , a n d t h e o v e r a l l

a c c u r a c y r a t e w a s . 9 1 . F o r b i n g e - e a t i n g d i s o r d e r , th e 1 - w e e k

t e s t - r e t e s t k a p p a c o e f f i c i e n t w a s . 7 5 , a n d t h e o v e r a l l a c c u r a c y r a t e

wa s . 89 .

W e a l so e x a m i n e d t h e t e m p o r a l s t ab i li t y o f t h e E D D S o v e r a l l

s y m p t o m c o m p o s i t e . T h e c o r r e l a t i o n c o e f f i c i e n t r e f l e c t i n g t h e

1 - w e e k t e s t - r e t e s t r e l i a b i l i t y w a s . 8 7 f o r t h i s c o m p o s i t e .

I n t e r n a l C o n s i s t e n c y

T h e i n t e rn a l c o n s i s te n c y o f t h e E D D S s y m p t o m c o m p o s i t e w a s

a s s e s s e d b y c a l c u l a t i n g C r o n b a c h s a l p h a f o r t h e s t a n d a r d i z e d

i t e m s t h a t m a k e u p t h i s s c o r e . ~ C r o n b a c h s a l p h a f o r t h e s y m p t o m

c o m p o s i t e w a s . 9 1 i n t h e f u l l s a m p l e a n d . 8 6 f o r t h e s u b s e t o f

p a r t i c ip a n t s ( N = 5 5 ) w h o c o m p l e t e d t h e E D D S 1 w e e k a ft e r

c o m i n g i n t o t h e l a b .

C r i t e r i o n V a l i d i t y

T h e c r i t e r i o n v a l i d i t y o f t h e E D D S w a s e x a m i n e d b y t e s t i n g

w h e t h e r , f o r e a c h e a t i n g d i s o r d e r , t h i s s c a l e a c c u r a t e l y d i s t i n -

g u i s h e d b e t w e e n i n t e r v i e w - i d e n t i f i e d p a r t i ci p a n t s w i t h t h e d i s o r d e r

a n d t h o s e w i t h o u t a n e a t i n g d i s o r d e r . T a b l e 2 p r e s e n t s t h e k a p p a

c o e f f i c i e n t , s e n s i t iv i t y , s p e c i f i c i t y , p o s i t i v e p r e d i c t i v e v a l u e , n e g -

a t i v e p r e d i c t i v e v a l u e , a n d o v e r a l l a c c u r a c y f o r e a c h e a t i n g d i s o r -

d e r . K a p p a r e p r e s e n t s t h e c h a n c e - c o r r e c t e d l e v e l o f a g r e e m e n t

b e t w e e n t w o n o m i n a l v a r i a b l e s , w h i c h , i n t h i s c a s e , w e r e t h e

T a b l e

Me a ns and S t andar d De v i a t i ons f o r A l l C on t i nuous

Me as u r e s U s e d in S t udy 2

Continuous measures

M SD

Eating Disorder Examination

Restraint 2.19 1.55

Eating concern 1.54 1.45

We ight concern 2.97 1.53

Shape concern 3.22 1.55

Ya le -Brown-Corne l l

Eating and weight preoccupations 6.25 4.64

Eating and weight rituals 5.53 5.01

Three-Factor Eating Questionnaire

Cog nitive restraint 10.95 5.11

Hunger 7.76 3.98

Disinhibition 10.28 4.31

EDD S Symp tom Composite 0.00 11.32

Note .

EDDS = Eating Disorder Diagnostic Scale. N = 367.

i n t e r v i e w d i a g n o s i s a n d t h e E D D S d i a g n o s i s f o r e a c h e a t i n g d i s -

o r d e r . S e n s i t i v i t y r e f le c t s t h e p r o p o r t i o n o f i n d i v i d u a l s w i t h a

p o s i t i v e i n t e r v i e w d i a g n o s i s w h o w e r e c o r r e c t l y i d e n t i f i e d b y t h e

E D D S . S p e c i f i c i t y r ef l e c t s t h e p r o p o r t i o n o f i n d i v i d u a l s w i t h a

n e g a t i v e i n t e r v i e w d i a g n o s i s w h o w e r e c o r r e c t l y i d e n t i f i e d b y t h e

E D D S . P o s i t i v e p r e d i c t i v e v a l u e r e p r e s e n t s t h e p r o p o r t i o n o f i n -

d i v i d u a l s w h o w e r e c l a s s i f i e d a s h a v i n g a p o s i t i v e d i a g n o s i s b y t h e

E D D S w h o a c t u a l l y m e t c r i t er i a fo r t h e d i a g n o s i s o n t h e s t r u ct u r e d

i n t e r v i e w . N e g a t i v e p r e d i c t i v e v a l u e r e p r e s e n t s t h e p r o p o r t i o n o f

i n d i v i d u a l s w h o w e r e c l a s s i f i e d a s h a v i n g a n e g a t i v e d i a g n o s i s b y

t h e E D D S w h o a c t u a l l y d i d n o t m e e t c r i t e r i a f o r t h e d i a g n o s i s o n

t h e s t r u c tu r e d i n t e r v i e w . A c c u r a c y i s th e p r o p o r t i o n o f i n d i v i d u a l s

f o r w h o m t h e n e g a t iv e a n d p o s i t i v e E D D S d i a g n o se s m a t c h e d t h e

a c t u a l i n t e r v i e w d i a g n o s e s .

T h e k a p p a c o e f f i c i e n t r e f l e c ti n g t h e a g r e e m e n t b e t w e e n t h e

d i a g n o s e s f r o m t h e s t r u c t u r ed i n t e r v i e w a n d t h e E D D S w a s . 9 3 f o r

a n o r e x i a n e r v o s a ; a n d t h e s e n s i t i v i t y , s p e c i fi c i t y , p o s i t i v e p r e d i c -

t i v e v a l u e , n e g a t i v e p r e d i c t i v e v a l u e , a n d a c c u r a c y w e r e a l l a b o v e

. 9 3 . T h e k a p p a c o e f f i c i e n t t h a t d e n o t e d d i a g n o s t i c a g r e e m e n t b e -

t w e e n t h e s t r u c t u r e d i n t e r v i e w a n d E D D S v / , as . 81 f o r b u l i m i a

n e r v o s a ; a n d t h e s e n s i t i v i t y , s p e c i f ic i t y , p o s i t i v e p r e d i c t i v e v a l u e ,

n e g a t i v e p r e d i c t i v e v a l u e , a n d a c c u r a c y w e r e a l l a b o v e . 8 1 . F i -

n a l l y , th e k a p p a c o e f f i c i e n t f o r d i ag n o s t i c a g r e e m e n t b e t w e e n t h e

i n t e r v i e w a n d E D D S d i a g n o s e s w a s . 7 4 f o r b i n g e - e a t i n g d i s o r d e r ;

a n d t h e s e n s i t i v i t y , s p e c i f ic i t y , p o s i t i v e p r e d i c t i v e v a l u e , n e g a t i v e

p r e d i c t i v e v a l u e , a n d a c c u r a c y w e r e a l l a b o v e . 7 7 .

C o n v e r g e n t V a l id i ty

I n a n e f f o r t t o g e n e r a t e e v i d e n c e o f c o n v e r g e n t v a l i d i t y , w e

t e s t e d w h e t h e r t h e E D D S - i d e n t i f i e d g r o u p s w i t h e a t i n g d i s o r d e r s

s h o w e d t h e e x p e c t e d e l e v a t i o n s o n v a l i d a t e d m e a s u r e s o f e a ti n g

d i s t u r b a n c e s r e l a t i v e t o E D D S - i d e n t i f i e d i n d i v i d u a l s w i t h n o n e a t -

i n g d i s o r d er s . P l a n n e d c o n t r a s t s i n a n a l y s i s o f v a r i a n c e ( A N O V A )

m o d e l s t h a t c o m p a r e d e a c h e a t i n g - d i s o r d e r g r o u p w i t h t h e

n o n e a t i n g - d i s o r d e r g r o u p w e r e u s e d t o a c c o m p l i s h t h i s a i m . W e

h y p o t h e s i z e d t h a t t h e t h r e e e a t i n g - d i s o r d e r g r o u p s w o u l d s h o w

e l e v a t i o n s o n t h e v a l i d a t e d m e a s u r e s o f e a t i n g d i s tu r b a n c e s r e l a -

t i v e t o t h e n o n d i s o r d e r g r o u p w i t h t w o e x c e p t i o n s . F i r s t , b e c a u s e

a n o r e x i a n e r v o s a i s m a r k e d b y e x t r e m e c a l o r i c r e s t r i c t i o n , w e d i d

n o t e x p e c t t h i s g r o u p t o s h o w e l e v a t i o n s i n d i s i n h i b i t e d e a t i n g .

S e c o n d , w e d i d n o t e x p e c t in d i v i d u a l s w i t h b i n g e - e a t i n g p a t h o l o g y

t o s h o w e l e v a t i o n s i n d i e t a r y r e s t r a i n t r e l a t i v e t o n o n e a t i n g -

d i s o r d e r c o n t r o l s b e c a u s e t h i s d i s o r d e r i s c h a r a c t e r i z e d b y e x c e s -

s i v e c a l o r ic i n t a k e i n t h e ab s e n c e o f c o m p e n s a t o r y b e h a v i o r s ( s u c h

a s e x t r e m e d i e t i n g ) .

T h e m e a n s a n d s t a n d a r d d e v i a t i o n s f o r e a c h o f t h e ea t i n g d i s -

t u r b a n c e s c a l e s a c r o s s t h e v a r i o u s e a t i n g - d i s o r d e r a n d c o n t r o l

g r o u p s a r e p r e s e n t e d i n T a b l e 3 , a l o n g w i t h t h e r e s u l t s o f t h e

p l a n n e d c o n t r a s ts a n d t h e p e r c e n t a g e o f v a r i a n c e a c c o u n t e d f o r i n

1 W e considered cond ucting confirmatory factor analysis, but decided

against this because the symptom overlap between eating disorders (e.g.,

the items on the importance of weight and shape on self-evaluation are

used for diagnoses o f anorexia nervosa and bulimia nervosa) w ould require

cross-loadings that would clo ud the interpretation o f the factors. Moreover,

the primary aim o f this scale was to pro vide eating-disorder

diagnoses and

we felt that a focus on the factoral structure wo uld eclipse the main purpose

of this scale.


5/9

EATIN G DISORDER DIAGNOSTIC SCALE

T a b l e 2

Agreement Between the EDDS Diagnoses and Structured Psychiatric Interview D iagnoses

Positive Negative

predictive predictive

Eating disorder K Sensitivity Specificity value valu e

Accuracy

Anorexia nervosa .93 .93 1.00 .93 1.00 .99

Buli mia nervosa .81 .81 .98 .86 .97 .96

Binge-eating disorder .74 .77 .96 .80 .95 .93

Note.

EDD S = Eating Disorder Diagnostic Scale. N = 367.

1 2 7

e a c h o u t c o m e b y t h e g r o u p i n g v a r i a b l e . 2 S t a t i s t i c a l s i g n i f i c a n c e

w a s a s s e s s e d w i t h t h e l e a s t s i g n i f i c a n t d i f f e r e n c e te s t . A s p r e -

d i c t e d , t h e e a t i n g - d i s o r d e r g r o u p s g e n e r a l l y s h o w e d e l e v a t i o n s i n

d i e t a r y r e s t r a i n t , e a t i n g , w e i g h t a n d s h a p e c o n c e r n s , e a t i n g a n d

w e i g h t p r e o c c u p a t i o n s a n d r i t u a l s, c o g n i t i v e r e st r a i n t , h u n g e r , a n d

d i s i n h i b i t i o n o n t h e v a l i d a t e d m e a s u r e s o f e a t i n g p a t h o l o g y . T h e s e

e f f e c ts a c c o u n t e d f o r b e t w e e n 6 t o 3 1 o f t h e v a r i a n c e i n t h e s e

o u t c o m e s . C o n s i s t e n t w i t h e x p e c t a t i o n s , t h e a n o r e x i a n e r v o s a

g r o u p d i d n o t s h o w e l e v a t i o n s o n d i s i n h i b i t e d e a t i n g , a n d t h e

b i n g e - e a t i n g d i s o r d e r g r o up d i d n o t s h o w e l e v a ti o n s o n t h e t w o

m e a s u r e s o f d i e t a r y r e s t ra i n t . H o w e v e r , t h e a n o r e x i a n e r v o s a g r o u p

d i d n o t r e p o r t h e i g h t e n e d l e v e l s o f h u n g e r o r w e i g h t a n d s h a p e

c o n c e r n s , th e b u l i m i a n e r v o s a g r o u p d i d n o t s h o w e l e v a t io n s o n t h e

c o g n i t i v e r e s t r a i n t s c al e , a n d t h e b i n g e - e a t i n g d i so r d e r g r o u p d i d

n o t e v i d e n c e g r e a t e r e a t i n g a n d w e i g h t r i t u a l s .

F i n a l l y , i n a n e f f o r t t o p r o v i d e e v i d e n c e f o r t h e c o n v e r g e n t

v a l i d it y o f th e E D D S s y m p t o m c o m p o s i t e, w e t e s te d w h e t h e r t h i s

c o m p o s i t e w a s p o s i t i v e l y c o r r e l a t e d w i t h t h e v a l i d a t e d m e a s u r e s o f

e a t i n g d i s tu r b a n c e s. A s r e f le c t ed i n T a b l e 4 , t h e s y m p t o m c o m -

p o s i t e s h o w e d s i g n i f i c a n t p o s i t i v e c o r r e l a t i o n s w i t h t h e v a l i d a t i o n

m e a s u r e s o f d i e t a r y r e s t r a i n t , e a t i n g , w e i g h t a n d s h a p e c o n c e r n s ,

e a t i n g a n d w e i g h t p r e o c c u p a t i o n s a n d r i tu a l s , h u n g e r , a n d d i s i n h i -

b i t i o n . T h e o n e e x c e p t i o n w a s t h a t th e E D D S s y m p t o m c o m p o s i t e

w a s n o t s i g n i f i c a n t l y c o r r e l a t e d w i t h t h e c o g n i t i v e r e s t r a i n t s c al e .

T h e s ig n i f i c a n t r e l a t io n s a c c o u n t e d f o r b e t w e e n 1 3 a n d 4 3 o f

t h e v a r i a n c e i n t h e s e v a l i d a t e d m e a s u r e s o f e a t i n g d i s t u r b a n c e s .

Discuss ion

T h e a i m o f t h i s s t u d y w a s t o d e v e l o p a b r i e f s e l f - r e p o r t s c a l e f o r

d i a g n o s i n g a n o r e x i a n e r v o s a , b u l i m i a n e r v o s a , a n d b i n g e - e a t i n g

d i s o r d e r , a n d t o p r o v i d e e v i d e n c e o f i t s r e l i a b i l i t y a n d v a l i d i t y . W e

a d a p t e d i t e m s f r o m v a l i d a t e d s t r u c t u r e d i n t e r v i e w s t h a t a s s e s s

e a t i n g p a t h o l o g y t o c r e a t e a o n e - p a g e s e l f - r e p o r t s c a l e . C o l l e c -

t i v e l y , f i n d i n g s f r o m o u r t w o s t u d i e s s u g g e s t e d t h a t th i s n e w s c a l e

w a s b o t h r e l i a b l e a n d v a l i d .

E v i d e n c e o f th e R e l i a b i li t y o f t h e E D D S

R e s u l t s s u g g e s t e d t h a t t h e E D D S p o s s e s s e d s a t i s f a c t o r y t e s t -

r e t e s t r e l i a b i l i t y i n t h i s i n v e s t i g a t i o n . T h e o v e r a l l l e v e l o f a g r e e -

m e n t f o r e a t i n g - d is o r d e r d i ag n o s e s b e t w e e n t h e t w o a d m i n i s t r a -

t i o n s o f t h e E D D S s e p a r a t e d b y a p e r i o d o f 1 w e e k w a s 9 8 f o r

a n o r e x i a n e r v o s a , 9 1 f o r b u l i m i a n e r v o s a , a n d 8 9 f o r b i n g e -

e a t i n g d i so r d e r , s u g g e s t i n g s t r o n g c o n c o r d a n c e b e t w e e n d i a g n o s e s

g e n e r a t e d b y t h e E D D S o v e r t i m e . T e s t - r e t e s t k a p p a c o e f f i c i e n t s

w e r e g o o d t o e x c e l l e n t a c c o r d i n g t o t h e c r i t e ri a p r o p o s e d b y F l e i s s

( 1 9 8 1 ) . T h e s e v a l u e s r e f l e c t a r e a s o n a b l y h i g h l e v e l o f t e s t - r e t e s t

r e l i a b i l i t y f o r a o n e - p a g e i n s t r u m e n t . M o r e o v e r , t h i s s c a l e c o m -

p a r e s f a v o r a b l y w i t h v a l i d a t e d p s y c h i a t r i c i n t e r v i e w s s u c h a s t h e

S C I D , w h i c h h a d t e s t - r e t e s t k a p p a c o e f f i c i e n t s r a n g i n g f r o m . 8 0 t o

. 9 0 f o r e a t i n g - d i s o r d e r d i a g n o s e s ( P i k e e t a l . , 1 9 9 5 ) a n d a n a v e r a g e

t e s t - r e t e s t k a p p a c o e f f i c i e n t a c ro s s A x i s I d i s o r d e r s o f . 4 6 i n p a s t

c l i n i c a l a n d c o m m u n i t y s t u d i e s ( e .g . , W i l l i a m s e t a l. , 1 9 9 2 ) . W e

c a n n o t c o m p a r e t h e t e s t - r e t e s t r e l i a b i l i t y o f o u r n e w s c a l e t o t h at

f o r t h e E D E b e c a u s e t h e t e s t - r e t e s t r e l i a b i l i ty o f E D E - g e n e r a t e d

d i a g n o s e s h a s n o t y e t b e e n r e p o r t e d . N o n e t h e l e s s , i t w a s n o t e w o r -

t h y t h a t t h e t e s t - r e t e s t r e l i a b i l i t y c o e f fi c i e n t s f o r b u l i m i a n e r v o s a

a n d b i n g e - e a t i n g d i s o r d e r w e r e l o w e r t h a n t h e c o e f f i c i e n t f o r

a n o r e x i a n e r v o s a . T h i s p a t t e r n o f f i n d i n g s l i k e l y r e s u l t e d f r o m t h e

c h a l l e n g e o f a c c u r a t e l y m e a s u r i n g b i n g e - e a t i n g f r e q u e n c y . A l t e r -

n a t i v e l y , th e r e i s s o m e p o s s i b i l i t y t h a t b u l i m i a n e r v o s a a n d b i n g e -

e a t i n g d i s o r d e r a r e s i m p l y l e s s t e m p o r a l l y s t a b l e t h a n a n o r e x i a

n e r v o s a .

D a t a a l s o i n d i c at e d th a t th e E D D S s y m p t o m c o m p o s i t e s h o w e d

h i g h t e s t - r e t e s t r e l i a b i l i t y o v e r a 1 - w e e k i n t e r v a l ( r = . 8 7 ). T h i s

e s t i m a t e a l s o c o m p a r e s f a v o r a b l y t o t h o s e f o r o t h e r w e l l - v a l i d a t e d

c o n t i n u o u s m e a s u r e s o f e a t i n g p a t h o l o g y , s u c h a s t h e t e s t - r e t e s t

c o e f f i c i e n t o f . 9 5 f o r th e B u l i m i a T e s t - - R e v i s e d ( T h e l e n e t a l. ,

1 9 9 1 ) , p a r t i c u l a r l y g i v e n t h a t t h e E D D S i s m u c h b r i e f e r .

T h e s y m p t o m c o m p o s i t e a l s o e v i d e n c e d a c c e p t a b l e i n t e r n a l

c o n s i s t e n c y a c r o s s i t e m s ( m e a n a = . 8 9) . T h e r e f o r e , i n a d d i t i o n t o

u s i n g t h e E D D S a s a b r i e f m e a s u r e o f e a t i n g - d i s o r d e r d i a g n o s e s , i t

a p p e a r s t h a t i t m a y a l s o b e u s e f u l a s a c o n t i n u o u s m e a s u r e o f

o v e r a l l e a t i n g - d i s o r d e r s y m p t o m a t o l o g y .

E v i d e n c e o f t h e V a l i d it y o f th e E D D S

T h e c u r r e n t f i n d i n g s a l so p r o v i d e d c o n s i d e r a b l e e v i d e n c e f o r t h e

v a l i d i t y o f t h e E D D S . F i r s t , t h e c o n t e n t v a l i d a t i o n s t u d y t h a t u s e d

e x p e r t r a t e rs s u g g e s t e d t h a t t h e r e l e v a n t

D S M I V

d i a g n o s t i c c r i t e -

r i a fo r t h e t h re e e a t i n g d i s o rd e r s w e r e i n c l u d e d o n t h e E D D S a n d

t h a t n o i r r e l e v a n t i n f o r m a t i o n w a s a s s e s s e d .

S e c o n d , a g r e e m e n t b e t w e e n t h e e a t i n g -d i s o r d e r d ia g n o s e s f r o m

t h e E D D S a n d t h o s e f r o m th e s tr u c t u r e d i n t e r v i e w s w a s 9 9 f o r

a n o r e x i a n e r v o s a , 9 6 f o r b u l i r n i a n e r v o s a , a n d 9 3 f o r b i n g e -

e a t i n g d i s o r d e r , w h i c h r e p r e s e n t e d g o o d t o e x c e l l e n t c o n c o r d a n c e .

C o l l e c t i v e l y , t h e s e r e s u l t s s u g g e s t . th a t t h e E D D S p o s s e s s e d a d e -

q u a t e c r i t e r i o n v a l i d i t y i n th i s i n v e s t i g a t i o n . T h e a g r e e m e n t b e -

2 The sam ple size (N = 217) for the convergent validity analyses was

smaller because the 3 anorexic patients recruited from the inpatient psy-

chiatric treatment unit, the 38 participants recruited from the affect study,

and the 109 participants recruited from the longitudinal risk factor study

did not complete the EDE subscales, YBC-EDS, or TFEQ.


6/9

1 2 8 STICE, TELC H , A N D R IZV I

T a b l e 3

Mean Differences Between EDDS Identified Eating Disorder Groups and Controls on Validated Eating Pathology Measures

Eat ing pathology measures

Non-eat ing

disordered

A n o re x i a n e rv o sa B u l i mi a n e rv o sa B i n g e -e a ti n g c o n t ro l s

(n = 18) (n = 39) d isorder (n = 57) (n = 103)

M SD M SD M SD M SD

%

variance

expla ined

Ea t i n g D i so rd e r Ex a m i n a t io n

Res traint 3.24 1.78a 2.98 1.37a 2.01 1.15 1.84 1.60b 11

Eat ing concern 2 .20 1 .43a 2.36 1.55a 1.83 1.29a 0.99 1.28b 14

W eight concern 2 .43 1 .93 3 .63 1 .27a 3.60 1.16a 2.48 1.53b 11

Sha pe con cern 2.83 1.83 4.13 1.28 a 3.95 1.06a 2.56 1.50b 18

Y a l e -B ro w n ~ C o rn e l l

Eatin g and we ight preo ccup ations 9.27 4.75a 8.95 3.07 a 6.36 4.68a 4.77 4.46b 15

Eat ing and weight r i tua ls 9 .46 4 .93 a 7 .82 4 .74a 4 .83 4 .64 4 .40 4 .75b 12

Th re e -Fa c t o r Ea t i n g Q u e s t i o n n ai re

Co gnitiv e restr aint 14.13 3.39~ 12.08 4.24 9.60 5.13 10.62 5.38b 6

Hu nge r 6.27 3.73 9.95 3.88 a 9.60 3.38a 6.40 3.65 b 18

Dis inhib ition 5.60 3.96 12.79 2.52 a 13.14 2.20a 8.85 4.29 b 31

Note. EDDS = Eat ing Disord er Diagnost ic Scale . M eans w i th d i fferen t subscrip ts are s ta ti s tical ly s ign i f ican t ly d i fferen t accord ing to the least s ign i f ican t

differ ence test . N = 217.

t w e e n t h e d i a g n o s e s g e n e r a t e d b y t h e E D D S a n d th e g o l d s ta n -

d a r d a p p r o a c h e d t h e u p p e r l i m i t o f w h a t c o u l d b e e x p e c t e d g i v e n

t h e r e l i a b i l i t y o f t h e m e a s u r e s . M o r e o v e r , t h e o b s e r v e d v a l i d i t y

c o e f f i c i en t s c o m p a r e f a v o r a b l y t o t h o s e f o r t h e S C I D ( K r a n z l e r ,

K a d d e n , B a b o r , & T e n n e n , 1 9 9 6) . N o n e t h e l e s s , it w a s n o t e w o r t h y

t h a t t h e c o n c o r d a n c e b e t w e e n t h e d i a g n o s e s f r o m t h e E D D S a n d

t h e i n t e r v i e w w a s s o m e w h a t l o w e r f o r b i n g e - e a t i n g d i s o r d e r t h a n

i t w a s f o r a n o r e x i a n e r v o s a a n d b u l i m i a n e r v o s a . T h e r e a r e a t le a s t

t w o f a c t o r s t h a t m i g h t h a v e c o n t r i b u t e d t o t h i s f in d i n g . F i r st , t h e

6 - m o n t h d u r a t i o n c r i t e r i o n f o r b i n g e - e a t i n g d i s o r d e r s y m p t o m s i s

l o n g e r t h a n t h e d u r a t i o n c r i t e r i a f o r b u l i m i a n e r v o s a o r a n o r e x i a

n e r v o s a , w h i c h m a y m a k e i t m o r e d i f f i cu l t fo r p e o p l e t o r e c a ll t h e i r

s y m p t o m d u r a t i o n a c c u r a t e l y ( H e n r y , M o f f i t t , C a s p i , L a n g l e y , &

S i l v a , 1 9 9 4 ) . S e c o n d , m o r e q u a l i fi e r s a r e r e q u i r e d f o r b i n g e e p i -

s o d e s t o m e e t DSM IV d i a g n o s t i c c r i t e r ia f o r b i n g e - e a t i n g d i s o r d e r

t h a n i s t h e c a s e f o r b u l i m i a n e r v o s a . I n a d d i t i o n t o t h e b i n g e - e a t i n g

r e q u i r e m e n t s f o r a d i a g n o s i s o f b u l i m i a n e r v o s a ( t h e p a r t i c i p a n t

T a b l e 4

Pearson Product Correlations Between the EDDS Symptom

Composite and the Validated Eating Pathology Measures

Corre la t ion wi th EDDS

Ea t i n g p a t h o lo g y me a su re s sy mp t o m c o mp o s i t e

Ea t i n g D i so rd e r Ex a m i n a t io n

Rest ra in t .36*

Eat ing concer n .54*

We ight concern .57*

Shape concer n .66*

Y a l e -B ro w n --C o rn e l l

Eat ing and weight p reoccupat ions .47*

Eat ing and weight r i tua ls .36*

Three-Factor Eat ing Quest ionnai re

Cogn i t ive rest ra in t .10

Hunger .53*

Disinh ib i t ion .63*

Note. EDD S = Eat ing Disorder Diagnost ic Scale , N = 217 .

p < .001.

m u s t c o n s u m e a l a r g e a m o u n t o f f o o d a n d f e e l o u t o f c o n t r o l ) ,

b i n g e - e a t i n g d i s o r d e r r e q u i r e s t h a t a t l e a s t t h r e e a d d i t i o n a l f e a t u r e s

a r e p r e s e n t d u r i n g b i n g e e a t i n g ( e . g . , e a t i n g m o r e r a p i d l y t h a n

n o r m a l , e a t i n g a l o n e b e c a u s e o f e m b a r r a s s m e n t a b o u t e a t i n g b e -

h a v i o r s ) a n d t h a t b i n g e e a t i n g r e s u l t i n m a r k e d d i s t r e s s . T h e

r e d u c e d c o n c o r d a n c e f o r b i n g e - e a t i n g d i s o r d e r m a y b e d u e t o t h e

f a c t t h a t p a r t i c i p a n t s h a d t o r e p o r t t h e e x a c t s a m e r e s p o n s e s t o

m o r e q u e s t i o n s o n t h e s c a l e a n d i n t h e i n t e r v i e w .

T h i r d , d a t a a ls o s u g g e s t e d t h a t t h e E D D S p o s s e s s e d c o n v e r g e n t

v a l i d i t y i n t h i s i n v e s t i g a t i o n , i n t h a t t h o s e i d e n t i f i e d a s h a v i n g a n

e a t i n g d i s o r d e r b a s e d o n t h e E D D S g e n e r a l l y s h o w e d e l e v a t e d

s c o r e s o n v a l i d a t e d m e a s u r e s o f e a t i n g d i s t u r b a n c e s r e l a ti v e t o

E D D S - i d e n t i f i e d w i t h n o e a t i n g d i s o r d e r s . A s h y p o t h e s i z e d ,

E D D S - i d e n t i f i e d e a t i n g - d i s o r d e r g r o u p s r e p o r t e d m o r e d i e t ar y r e -

s t r a i n t , h u n g e r , a n d d i s i n h i b i t e d e a t in g , a s w e l l a s g r e a t e r e a t i n g ,

w e i g h t a n d s h a p e c o n c e r n s a n d r i t u al s , t h a n d i d E D D S - i d e n t i f ie d

c o n t r o ls . M o r e o v e r , t h e E D D S s y m p t o m c o m p o s i t e c o r r e l a te d

p o s i t iv e l y w i t h t h e s e s a m e v a l i d a t e d m e a s u r e s o f e a t i n g p a th o l o g y .

T h e m a g n i t u d e o f t h e s i g n i f i c an t r el a t io n s r a n g e d f r o m m e d i u m t o

l a r g e e f f e c t s iz e s a c c o r d i n g t o t h e c r i t e r ia p r o p o s e d b y C o h e n

( 1 9 8 8 ). T h e r e w e r e a f e w n o n s i g n i f i c a n t g ro u p d i f f e r e n c e s t h a t

w e r e p r e d i c t e d a p r i o r i . C o n s i s t e n t w i t h e x p e c t a t i o n s , t h e b i n g e -

e a t i n g d i s o r d e r g r o u p d i d n o t e v i d e n c e h e i g h t e n e d d i e t a r y r e s t ra i n t.

A g a i n , i n d i v i d u a l s w i t h b i n g e - e a t i n g d i so r d e r w e r e n o t e x p e c t e d t o

s h o w e l e v a t i o n s i n d i e t a r y r e s t r a i n t b e c a u s e t h i s d i s o r d e r i s c h a r -

a c t e r iz e d b y e x c e s s i v e c a l o r ic i n t a k e i n t h e a b s e n c e o f c o m p e n s a -

t o r y b e h a v i o r s . A l s o a s p r e d i c t e d , t h e a n o r e x i c g r o u p d i d n o t s h o w

e l e v a t e d d i s i n h i b i t i o n r e l a t i v e t o c o n t r o l s . P r e s u m a b l y , t h i s g r o u p

d i d n o t s h o w g r e a t e r d i s in h i b i t e d e a t i n g b e c a u s e a n o r e x i a n e r v o s a

i s m a r k e d b y e x t r e m e c a l o r i c r e s t r i c t i o n .

H o w e v e r , t h e r e w e r e a l s o t h r e e u n e x p e c t e d f i n d i n g s i n th e

c o n v e r g e n t v a l i d i t y a n a l y s e s . F i r s t , t h e a n o r e x i c g r o u p d i d n o t

r e p o r t g r e a t e r h u n g e r o r e l e v a t e d w e i g h t a n d s h a p e c o n c e r n s c o m -

p a r e d w i t h n o n - e a t i n g d i s o r d e r c o n t r o l s . T h i s m a y r e f l e c t t h e

e x t r e m e d e n i a l t h a t c h a r a c t e r i z e s a n o r e x i a n e r v o s a ( V i t o u s e k ,

W a t s o n , & W i l s o n , 1 9 9 8 ) . I n d e ed , t h e f a c t t h a t E D D S - i d e n t i f i e d

a n o r e x i c p a r t i c i p a n t s d e n i e d h u n g e r w h e n t h e y h a d a m e a n B M I


7/9

E A T I N G D I S O R D E R D I A G N O S T I C S C A L E 1 2 9

sc ore of 15 .5 (m e a n we i ght -- - 87 lbs . a nd m e a n he i ght = 5 f t 3 in . )

c l e a r l y s u g g e s t s t h e y w e r e i n d e n i a l . S i m i l a r l y , i t s e e m s u n l i k e l y

t h a t t h e s e i n d i v i d u a l s w o u l d h a v e r e s t r i c t e d t h e i r c a l o r i c i n t a k e

s e v e r el y e n o u g h t o h a v e a c h i e v e d t h i s l o w w e i g h t u n l e s s t h e y h a d

e l e v a t e d w e i g h t a n d s h a p e c o n c e r n s . T h e s e f i n d i n g s u n d e r s c o r e t h e

d i f f i c u l t y o f m e a s u r i n g a d i s o r d e r c h a r a c t e r i z e d b y d e n i a l w i t h a

s e l f - r e p o r t i n s t r u m e n t . S e c o n d , E D D S - i d e n t i f i e d b i n g e - e a t i n g d i s -

o r d e r i n d i v i d u a l s d i d n o t r e p o r t h e i g h t e n e d e a t i n g a n d w e i g h t

r i t u a ls r e l a t i v e to c o n t r o l s o n t h e Y B C s u b s c a le . P e r h a p s i n d i v i d -

u a l s w i t h b i n g e - e a t i n g d i s o r d e r d o n o t e n g a g e i n e l a b o r a t e e a t i n g

a n d w e i g h t r i tu a l s ( e .g . , c o n s t a n t w e i g h i n g a n d c o m p u l s i v e c a l o r i e

c o u n t i n g ) b e c a u s e t h i s e a t i n g d i s o r d e r i s l e ss r o o t e d i n t h e p u r s u i t

o f t h e t h i n i d e a l t h a n i s a n o r e x i a a n d b u l i m i a n e r v o s a . T h i r d , t h e

b u l i m i c g r o u p d i d n o t r e p o r t g r e a t e r d i e t a r y r e s t r ai n t t h a n c o n t r o l s

o n o n e o f t h e t w o r e s t r a in t m e a s u r e s , a n d t h i s s a m e s c a l e d i d n o t

c o r r e l a t e s i g n i f i c a n t l y w i t h t h e E D D S s y m p t o m c o m p o s i t e . O n e

p o s s i b i l i t y s u g g e s t e d b y t h e f a c t t h a t th e e f f e c t s w e r e l a r g e r f o r t h e

E D E r e s t r a i n t s c a le t h a n f o r th e T F E Q c o g n i t i v e r e st r a i n t m e a s u r e

w a s t h a t t h e f o r m e r i s s i m p l y m o r e s e n s i t i v e . A l t e r n a t i v e l y , i t h a s

b e e n p r o p o s e d t h a t t h e T F E Q t a p s s u c c e s s f u l d i e t i n g ( H e a t h e r t o n ,

H e r m a n , P o l i v y , K i n g , & M c G r e e , 1 9 8 8 ) , an d i t m a y b e t h a t

i n d i v i d u a l s w i t h e a t i n g d i s o r d e r s, s u c h a s b u l i m i c a n d b i n g e - e a t i n g

d i s o r d e r i n d i v i d u a l s , d o n o t e n g a g e i n e f f e c t i v e d ie t i n g . F i n a l l y , th e

n o n s i g n i f i c a n t f i n d i n g f o r t h e T F E Q r e s t r a i n t s c a l e m a y a l s o h a v e

b e e n r e l a t e d t o t h e c h a l l e n g e o f m e a s u r i n g d i e t a r y r e s t r i c t i o n

w i t h i n t h e c o n t e x t o f r e g u l a r b i n g e e a t i n g .

L i m i t a t i o n s

A l t h o u g h t h i s s t u d y u t i l i z e d a l a r g e m u l t i s i t e s a m p l e , i n c o r p o -

r a t e d s t r u c tu r e d p s y c h i a t r i c i n t e r v i e f f s , a n d a t t e m p t e d t o p r o v i d e a

w i d e r a n g e o f e v i d e n c e f o r t h e r e l i a b i l it y a n d v a l i d i t y o f t h e E D D S ,

s e v e r a l l i m i t a t i o n s d e s e r v e c o m m e n t . F i r s t , t h e f a c t t h a t o n l y

f e m a l e i n d i v i d u a l s w e r e i n c l u d e d i n t h e p r e s e n t s a m p l e o b v i o u s l y

p r e c l u d e s g e n e r a l i z a t i o n t o m a l e i n d i v i d u a l s . F u t u r e r e s e a r c h w i l l

b e n e c e s s a r y t o e s t a b l i s h t h e r e l ia b i l i t y a n d v a l i d i t y o f th e E D D S

f o r m a l e i n d i v i d u a l s . S e c o n d , t h e f a c t t h a t p a r t i c i p a n t s f o r t h i s

i n v e s t i g a t i o n w e r e d r a w n f r o m a v a r i e t y o f s o u r c e s m a k e s i t

s o m e w h a t d i f f i c u l t t o k n o w t o w h i c h p o p u l a t i o n t h e s e f in d i n g s c a n

b e g e n e r a l i z e d . T h u s , c a u t i o n s h o u l d b e e x e r c i s e d i n g e n e r a l i z i n g

t h e s e r e s u l t s . T h i r d , i t w o u l d h a v e b e e n i d e a l t o h a v e r e p l i c a t e d

t h e s e p s y c h o m e t r i c a n a l y s e s i n a n i n d e p e n d e n t s a m p l e t o p r o v i d e

e v e n g r e a t e r c o n f i d e n c e i n t h e s t a b i l i t y o f t h e s e r e l i a b i l i t y a n d

v a l i d i t y e s t i m a te s . F o u r t h , t h e t e s t - r e t e s t c o e f f i c i e n t s f o r d i a g n o s e s

s h o u l d b e i n t e r p r e t e d w i t h c a u t i o n b e c a u s e o f t h e m o d e r a t e s a m p l e

s i z e f o r t h o s e a n a l y s e s. O n a r e l a t e d n o t e , t h e n u m b e r o f p a r ti c i -

p a n t s i n s o m e o f t h e e a t i n g - d i s o r d e r g r o u p s w a s m o d e s t ( e . g . , t h e r e

w e r e o n l y 1 5 p a r t i c ip a n t s w i t h a n o r e x i a n e r v o s a ) , w h i c h l i m i t s t h e

c o n f i d e n c e t h a t c a n b e p l a c e d i n t h e f i n d i n g s .

C o n c l u s i o n

T h i s s t u d y p r o v i d e d e v i d e n c e t h a t t h e E D D S s h o w e d c o n t e n t

v a l i d i t y ; t h a t t h e E D D S - d e r i v e d e a t i n g - d i s o r d e r d i a g n o s e s p o s -

s e s s e d t e s t - r e t e s t r e l i a b i l i t y , c r i t e r i o n v a l i d i t y , a n d c o n v e r g e n t

v a l i d i t y ; a n d t h a t t h e E D D S s y m p t o m c o m p o s i t e s h o w e d t e s t -

r e t e s t r e l i a b i l i t y , i n t e r n a l c o n s i s t e n c y , a n d c o n v e r g e n t v a l i d i t y .

C o l l e c t i v e l y , r e s u lt s f r o m t h i s p r e l i m i n a r y i n v e s t i g a t i o n i n d i c a t e d

t h a t t h e E D D S s h o w e d r e a s o n a b l e p s y c h o m e t r i c q u a l i t i e s . T h e

b e n e f i t s o f t h i s s c a l e a r e t h a t i t c a n b e c o m p l e t e d q u i c k l y a n d

e a s i l y , a n d t h a t i t is i n e x p e n s i v e b e c a u s e i t is n o t n e c e s s a r y t o t r a i n

o r p a y i n t e r v i e w e r s . T h u s , i t a p p e a r s t h a t t h i s s c a l e m i g h t u l t i -

m a t e l y p r o v e u s e f u l f o r t h e a s s e s s m e n t o f e a t i n g d i s o r d e r s i n

e t i o l o g i c , p r e v e n t i o n , a n d t r e a t m e n t r e s e a r c h a p p l i c a t i o n s , a s w e l l

a s in t r a d i t iona l c l in ic a l s e t t ings , whe re s t ruc ture d psyc hia t r i c

i n t e r v i e w s a r e l e s s f e a s i b l e .

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A p p e n d i x A

S c o r i n g A l g o r i t h m f o r E a t i n g D i s o r d e r D i a g n o s i s S c a l e ( E D D S )

T h e s c o r i n g a l g o r i t h m f o r E D D S e a t i n g d i s o r d e r d i a g n o s e s p a r a l le l s

t h a t u s e d f o r t h e E a t i n g D i s o r d e r E x a m i n a t i o n ( E D E ) . C o m p u t e r i z e d

s c o r i n g s t a t e m e n t s a r e o r d e r e d s u c h t h a t b u l i m i a n e r v o s a d i a g n o s e s

p r e e m p t b i n g e - e a t i n g d i s o r d e r d i a g n o s e s , a n d a n o r e x i a n e r v o s a d i a g -

n o s e s p r e e m p t b u l i m i a n e r v o s a d i a g n o s e s . T h e c o m p u t e r c o d e i s a v a i l -

a b l e f r o m E r i c S t i c e .

A n o r e x i a N e r v o s a

A d i a g n o s i s o f

D S M - 1 V

a n o r e x i a n e r v o s a i s m a d e i f a n i n d i v i d u a l

r e p o r t s ( a) h e i g h t a n d w e i g h t d a t a o n E D D S I t e m s 1 9 a n d 2 0 t h a t re s u l t

i n a b o d y m a s s i n d e x ( B M I = K g / M 2 ) o f l e s s t h a n 1 7 , 5, ( b ) a fe a r o f

w e i g h t g a i n o r b e c o m i n g f a t a s in d e x e d b y a s c o r e o f 4 o r g r e a t e r o n

E D D E I t e m 2 , ( c ) u n d u e i n f l u e n c e o f b o d y w e i g h t o r s h a p e o n s e l f -

e v a l u a t i o n a s i n d e x e d b y a s c o r e o f 4 o r g r e a t e r o n e i t h e r E D D S I t e m 3

o r 4 , a n d ( d ) a m e n o r r h e a i n p o s t m e n a r c h e a l f e m a l e s a s i n d e x e d b y a 3

o n E D D S I t e m 2 1 . F o l l o w i n g t h e E D E s c o r i n g a l g o r i t h m , i f a n i n d i -

v i d u a l m e e t s t h e f i r s t a n d f o u r t h c r i t e r i a a b o v e , i t i s n o t n e c e s s a r y f o r

t h e i n d i v i d u a l t o e n d o r s e t h e s e c o n d a n d t h i r d c ri t e ri a . F u r t h e r , b e c a u s e

o r a l c o n t r a c e p t i v e s c a n r e s u l t i n a r e g u l a r m e n s t r u a l c y c l e , t o b e o n t h e

c o n s e r v a t i v e s i d e , p a r t i c i p a n t s w h o w e r e t a k i n g o r a l c o n t r a c e p t i v e s t h a t

m e t t h e l o w w e i g h t c r i t e r i a w e r e c o d e d a s a m e n o r r h e i c . T h i s a p p r o a c h

i s a l s o u s e d i n t h e E D E .

B u l i r n i a N e r v o s a

A d i a g n o s i s o f D S M - I V bu l i mi a ne r vo sa i s ma de i f a n i nd i v i dua l r e por t s

( a ) r e gu l a r e a t i ng b i nge s ma r ke d by a pe r c e i ve d l o s s o f c on t r o l a nd t he

c o n s u m p t i o n o f a l a r g e a m o u n t o f f o o d a s i n d e x e d b y a r e s p o n s e o f yes to

E D D S I t e m 5 , a

yes

t o E D D S I t e m 6 , a n d a r e s p o n s e o f g r e a te r th a n 2 o n

E D D S I t e m 8 ; ( b ) r e g u la r u s e o f c o m p e n s a t o r y b e h a v i o r s a s in d e x e d b y a

r e spon se o f 8 o r g r e a t e r on t he sum o f E D D S I t e m s 15 , 16 , 17 , a nd 18 ; a nd

( c ) undue i n f l ue nc e o f body w e i gh t o r sha pe on s e l f - e va l ua t i on a s i nde xe d

by a s c o r e o f 4 o r g r e a t e r on e i t he r E D D S I t e m 3 o r 4 .

B i n g e - E a t i n g D i s o r d e r

A d i a g n o s i s o f

D S M - I V

b i nge - e a t i ng d i so r de r i s ma de i f a n i nd i v i dua l

r e por t s ( a ) re gu l a r e a t i ng b i nge s ma r ke d b y a pe r c e i ve d l o s s o f c on t r o l a nd

t h e c o n s u m p t i o n o f a l a r g e a m o u n t o f f o o d a s i n d e x e d b y a r e s p o n s e o f

yes

t o E D D S I t e m 5 , a yes t o E D D S I t e m 6 , a nd a r e sponse o f g r e a t e r t ha n 2

on E D D S I t e m 7 ; ( b ) a n e ndo r se me n t o f a t l e a s t th r e e o f t he f e a t u r e s t ha t

m a y b e a s s o c i a t e d w i th b i n g e e a t i n g a s i n d e x e d b y

ay e s

r e sponse t o a t l e a s t

t h r e e o f t he f e a t u r e s de sc r i be d i n E D D S I t e ms 9 , 10 , 11 , 12 , a nd 13 ; ( c )

ma r ke d d i s t r e s s r e ga r d i ng b i nge e a t i ng a s i nde xe d by a

yes

r e s p o n s e t o

E D D S I t e m 1 4 ; an d ( d ) t h e a b s e n c e o f a n y c o m p e n s a t o r y b e h av i o r s a s

r e f l e c t e d by a 0 r e spon se to E D D S I t e m s 15 , 16 , 17 , a nd 18 .


9/9

E A T I N G D I S O R D E R D I A G N O S T I C S C A L E

A p p e n d i x B

E a t i n g S c r e e n

1 3 1

P l e a s e c a r e f u l l y c o m p l e t e a l l q u e s t i o n s .

O v e r t h e p a s t 3 m o n t h s . . . N o t a t a l l S l i g h tl y M o d e r a t e l y E x t r e m e l y

1 . Ha ve you fe l t fa t ? 0 1 2 3 4 5 6

2 . H a v e y o u h a d a d e f m i t e f e a r t h a t y o u 0 , 1 2 3 4 5 6

m i g h t g a i n w e i g h t o r b e c o m e f a t ?

3 . H a s y o u r w e i g h t i n f l u e n c e d h o w y o u 0 1 2

Development and Validation of the Eating Disorder Diagnostic Scale

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