JOURNAL OF

AFFECTIVE DISORDERS

ELSEVIER Journal of Affective Disorders 41 (1996) 89-92

Research report

Does the duration of illness before treatment affect the time taken to recover on treatment in severely depressed women?

Philip Wilkinson ‘, Keith Hawton b, * , Bernice Andrew ‘, Joan Fagg b

iI Fair Mile Hospitul, Wullingfbrd, Oxford OX10 9HH, UK b Department qf Ps.hiatc. Warmford Hospital. O.rford, OX3 7JX, UK

Received 31 January 1996; revised 3 July 1996; accepted 3 July 1996

Abstract

This study examines the link between duration of depression before treatment is introduced and the duration of depressive illness after treatment in a population of 59 female psychiatric inpatients. Most women were suffering with severe

depression and the majority had had previous depressive illnesses. Calculation of the rank order correlation coefficient demonstrated no significant correlation between the duration of depression before initiation of treatment and the duration after treatment was introduced. This finding is discussed in relation to other relevant studies.

Keywords: Depression; Antidepressant; Treatment outcome

1. Introduction

There has been recent interest in the treatment of depressive illness about a possible link between the

length of the period before treatment is commenced and the eventual duration of illness (Scott, 1993). If the period before commencement of treatment does

predict response to treatment then there is a strong

case for initiating treatment as soon as possible. Scott et al. (1992) provide support for a link between

time of initiation of treatment and subsequent dura- tion of depression in a prospective study of newly referred patients (presumed to be outpatients). The relationship reached statistical significance only when active treatment was defined as the prescription of

* Corresponding author.

7.5 mg or more of a tricyclic antidepressant, or an

equivalent dose of another antidepressant. However, Scott (1993) went on to predict that the correlation would be enhanced if active treatment were defined as at least 150 mg of a tricyclic antidepressant.

The results of earlier studies also support the view

that duration of illness before treatment will affect

outcome. In a group of depressed outpatients, Kiloh et al. (1962) demonstrated a good response to

imipramine if treatment was introduced before symp-

toms has persisted for 1 year, rather than later. Deykin and DiMascio (1972) studied 163 depressed women treated mainly as outpatients and showed that the shorter the duration of illness before com- mencement of treatment, the better the degree of symptom reduction after treatment began; non-re- sponders were more likely to have been ill for over 6 months. In a study by Black et al. (1989) comparing electroconvulsive therapy (ECT) with tricyclics at a

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90 P. Wilkinson et al. / Joumul of Affeecrirr Disorders 41 (19961 X9-92

range of doses, response to ECT was also poorer in those who had been ill for over 2 years.

Other studies have failed to support the hypothe- sis. Reviewing eight placebo-controlled trials of an- tidepressant treatment, Khan and Brown ( 199 1) con-

clude that although placebo response is lost after an illness duration of 1 year, response to antidepressants

is unrelated to episode duration. Similarly, in a group

of outpatients, Downing and Rickels (1973) demon-

strated a loss of placebo response but no difference in response to antidepressant treatment between those who had been depressed for more than 6 months and those who had been depressed for 6 months or less.

Tbis paper reports the findings of a study which has examined the relationship between treatment-free

interval and illness duration after initiation of treat-

ment in a group of severely depressed female psychi- atric inpatients.

2. Method

2. I. Study population

The study population consisted of 59 female psy- chiatric inpatients suffering from major depressive disorder (Spitzer et al., 1978) without evidence of

other underlying psychiatric disorder, who were ad- mitted consecutively to four acute admission wards

in Oxford. Three further patients refused to be inter- viewed, and their results are excluded. The same

group of patients was previously investigated in rela-

Table I Characteristics of the women (n = 59) included in the investiga-

tion

Mean age (SD)

years 48.4 (15.1)

range 21-76

Number of previous episodes of depression

0 12 (20%)

l-2 25 (437cc)

3+ 22 (37%)

Previous hospital admission because of depression 39 (66%)

Mean (SD) BDI score 33.2 (12.0)

range lo-61

Mean (SD) MADRS score 31.7 (6.9)

Endogeneity score of 6 or more 53 (85%;)

After- Andrew et at. (1993).

tion to psychosocial influences on the outcome of

depression (Andrew et al., 1993). In general, they suffered from severe depression, as evidenced by

their scores on the Beck Depression Inventory (BDI;

Beck et al., 1961) and the Montgomery Asberg

Depression Rating Scale (MADRS; Montgomery and Asberg. 1979) and the majority suffered with en-

dogenous depression as determined using the New-

castle scale (Camey and Sheffield, 1972) (Table 1).

Four out of five had had previous episodes of de- pression and two thirds had previously been admitted

for psychiatric inpatient care.

In the original study (Andrew et al., 1993) after

an extensive initial assessment within a week of

admission to hospital, the women were reassessed in

detail immediately prior to discharge, at 3 months after admission and 9 months following discharge.

Recently, a 4-5 year interview follow-up study of

these women has also been conducted (Sherrington

et al, in preparation). At the original interview the time of onset of depression was recorded. At all the

subsequent assessments the course of the depressive disorder since the previous interview was investi-

gated. Recovery was defined as 8 weeks following the point when Research Diagnostic Criteria for ma-

jor depression were no longer met (Keller et al., 1982).

2.3. Assessment of treatment received

The original research interviews or, where neces-

sary, the patients’ casenotes were consulted to iden- tify the point at which treatment was commenced and the nature of the treatments received. This al- lowed calculation in weeks of the duration of the

illness before treatment and the duration of illness from treatment to recovery. The nature of treatment

received was also recorded, including the dose of antidepressant reached.

2.4. Statistical analysis

Analysis was conducted using SPSSX (SPSSX Inc., 1983). The Spearman’s rank order correlation coefficient was calculated for the comparison of the

P. Wilkinson et al./Journal of Affective Disorders 41 (1996) 89-92 91

interval before initiation of treatment with the dura-

tion of depression after treatment onset.

3. Results

3. I. Treatment received

Of the 59 women, 27 were treated with tricyclic

antidepressants alone or in combination with lithium;

in six of these cases, tricyclic doses remained at 75 mg or below. 21 were treated with electroconvulsive

therapy and antidepressants. 6 were treated with monoamine oxidase inhibitors, and 3 with mianserin.

One patient received oral flupenthixol only and an- other received no antidepressant treatment at all.

3.2. Duration of episodes

The mean duration of depression before treatment was commenced was 9.2 weeks, and the mean period

after treatment until recovery was 17.4 weeks.

3.3. Relationship between treatment-free interval and

illness duration after treatment

The Spearman’s rank order correlation coefficient for duration of post-treatment depression and treat-

ment-free interval before onset of adequate treatment was - 0.0678 (P = 0.616); Thus, there was no indi- cation of a relationship between the timing of intro-

duction of antidepressant treatment and the time

taken for subsequent recovery.

4. Discussion

This study set out to test the hypothesis that early treatment in a depressive episode will improve out-

come by reducing episode duration, in a group of women with severe depression. To test this, the correlation was measured between the period before treatment onset and the period from this time. The findings indicate that there was no appreciable corre- lation.

The finding of this study is at variance with those reported by some authors of a longer duration of depression after initiation of treatment the longer the

delay before treatment is started (Scott et al., 1992;

Deykin and DiMascio, 1972; Kiloh et al., 1962;

Black et al., 1989). One explanation might be differ- ences between the study populations. Firstly, most of

the subjects of this investigation had had at least one previous episode and all suffered with severe illness,

which usually shows a good response to antidepres- sant treatment (Joyce, 1992). Secondly, two thirds had previously been admitted because of depression

and might, therefore, have responded differently to

treatment than the outpatient populations included in

other studies. This study did not include investiga-

tion of the reasons for admission but it is to be expected that these would include a failure of outpa- tient treatment. Thirdly, the majority of patients suf-

fered with endogenous depression, a feature which

has previously been shown to predict better response to treatment (Paykel et al., 1974). Another factor

might relate to differences in the duration of the treatment-free interval. In this study, probably be- cause patients were mostly already known and some

were in psychiatric follow-up, they tended to receive

treatment quite soon, at a mean of 9 weeks from onset and no later than 40 weeks. In other studies,

treatment-free intervals associated with non-response

were of many months duration (Black et al., 1989; Kiloh et al., 1962; Deykin and DiMascio, 1972).

Overall, therefore, the findings of this investiga-

tion suggest that in women with severe depression who receive treatment relatively early after the onset

of their illnesses there is no association between treatment-free interval and outcome in terms of time

taken to recover from depression. This finding does not of course mean that prompt introduction of treat-

ment is not important, especially because of the risk of effects of persistent depression on interpersonal

relationships and other aspects of social adjustment.

It may also be crucial in the prevention of suicide in this highly at-risk population.

Acknowledgements

We thank Dr. Jean Sherrington and Mr. David Westbrook for their assistance with the data collec- tion. This study was based largely on information collected in two investigations, both being funded by grants from Oxford Regional Health Authority.

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