Factor structure and validation of the Obsessive Compulsive Inventory-Revised (OCI-R) in a

Greek non-clinical sample

Ioannis Angelakis1-2* Maria Panagioti 3 & Jennifer L. Austin2

1Panteion University, Athens, Greece;

2University of South Wales, School of Psychology, Pontypridd, Wales, UK;

3Institute of Population Health, University of Manchester, UK

RUNNING HEAD: FACTOR STRUCTURE AND VALIDATION OF A

HELLENIC VERSION OF OCI-R

*Correspondence: Dr Ioannis Angelakis, University of South Wales, School of Psychology,

Pontypridd, Wales, CF37 1DL, e-mail: ioannis.angelakis@southwales.ac.uk

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Abstract

This study assessed and validated a Greek version of the Obsessive-Compulsive Inventory-Revised

(OCI-R) in a large community sample. A total of 1379 Greek adults, including university students

and individuals from the community, participated. Overall, the Greek OCI-R supported the six-

factor solution, namely checking, ordering, obsessing, hoarding, washing and neutralizing, which

was suggested by the original scale development and was later confirmed in other cultural settings.

OCI-R was found to have very good to excellent psychometric properties as demonstrated by the

application of traditional and alternative validating methods. Further, a five-factor structure that

excluded the hoarding scale provided a slightly better conceptual fit of the data. In light of new

recommendations, the Greek version of OCI-R provides compelling evidence of its efficacy to

clearly differentiated between high- and low self-reports of OCD symptoms. We discuss that scores

from the Greek community sample were commensurate with those observed in clinical samples.

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Factor structure and validation of the Obsessive Compulsive Inventory-Revised (OCI-R) in a Greek

non-clinical sample

Obsessive-Compulsive Disorder (OCD) is a disabling mental health illness characterized by

recurrent intrusive thoughts and repetitive covert or overt acts, namely obsessions and compulsions,

which elicit a considerable degree of discomfort to the sufferer (American Psychiatric Association,

2000, 2013). OCD has been described as a highly heterogeneous disorder, which makes its clinical

presentation and subsequent treatment difficult to understand and manage (Lochner & Stein, 2006;

Mataix-Cols, Rosario-Campos, & Leckman, 2005). Recently, it was removed from the anxiety

disorders chapter to compose a new clinical entity of obsessive-compulsive and related disorders

according to DSM-5 (American Psychiatric Association, 2013). OCD shares some common

characteristics with a number of other clinical syndromes, such as Body Dysmorphic disorder

(BDD) and Hoarding disorder (HD), which now are reflected in the diagnostic criteria for these

disorders. However, the unique features of each of these conditions still allow their classification as

separate mental disorders. Although changes to the criteria and methodological limitations (e.g.,

Angst et al., 2004; Gibbs, 1996) render an estimate of its prevalence difficult, epidemiological

studies suggest that the lifetime OCD prevalence varies from 1.5% to 3.5% (Angst et al., 2004;

Crino, Slade, & Andrews, 2005; Subramaniam, Abdin, Vaingankar, & Chong, 2012), whereas

28.2% of the general population report OCD symptoms at least once in their lifetime (Ruscio, Stein,

Chiu, & Kessler, 2010).

Numerous studies highlight the distress and apprehension that obsessions and compulsions

cause to people with OCD (e.g., Veale & Roberts, 2014). Further, OCD is associated with great

reductions in quality of life and severe impairments in social and occupational functioning (Bobes,

Gonzalez, Bascaran, Arango, Saiz, & Bousono, 2001; Subramaniam, Soh, Vaingankar, Picco, &

Chong, 2013). Consequently, a number of self-report measures have been developed to diagnose

OCD and to assess the frequency and severity of OCD symptoms. The most well-known of these

measures is the Obsessive-Compulsive Inventory - Revised (OCI-R), which was developed to

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assess the full dimensions of OCD symptoms and their severity, as well as the overall distress

caused from these experiences (Foa, et al., 2002).

OCI-R is a shortened version of the Obsessive-Compulsive Inventory (OCI) (Foa, Kozak,

Salkovskis, Coles, & Amir, 1998). The main advantage of OCI-R is that it requires less time to be

completed than the original OCI. In comparison to the 42-item structure of OCI, OCI-R consists of

only 18 items, which measure symptom severity on a 5-point Likert-type scale and form six sub-

scales of the most common symptom categories encountered in OCD patients, including a washing,

checking, ordering, obsessing, hoarding and neutralizing category. The OCI-R has been found to

have excellent psychometric properties (Foa, et al., 2002; Hajcak, Huppert, Simons, & Foa, 2004).

In particular, OCI-R has shown very good to excellent internal consistency, test-retest reliability

and convergent validity both in clinical populations and in normal controls.

Other self-report measures for OCD also have been devised, but deemed insufficient for a

variety of reasons. For instance, Maudsley Obsessive-Compulsive Inventory (MOCI) (Hodgson &

Rachman, 1977) has received major criticism because it has poor internal consistency and also fails

to fully capture all the symptoms of OCD (Thordarson, Radomsky, Rachman, Shafran, Sawchuk, &

Hakstianet, 2004). Other self-report measures, such as the Padua Inventory of Obsessive-

Compulsive Symptoms (Sanavio, 1988) or the Vancouver Obsessional Compulsive Inventory

(Thordarson, et al., 2004), also have been criticized due to their large size and the prolonged time

required for their completion. Fairly recently, Abramowitz et al. (2010) developed the Dimensional

Obsessive-Compulsive Scale (DOCS) to capture and assess the heterogeneous nature of the OCD

symptomatology. Although DOCS has been found to be a sound measure of OCD, it also can be

time consuming to administer. Further, its properties have not yet fully been re-examined across

diverse cultural settings.

On the contrary, several studies have translated and validated OCI-R in different cultural

settings, including Spain, Germany, France, Korea, China, Turkey and Iceland, verifying that the

scale has very good or excellent psychometric properties (Aydin, Boysan, Kalafat, Selvi, Besiroglu,

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& Kagan, 2014; Fullana, Tortella-Feliu, Caseras, Andion, Torrubia, & Mataix-Cols, 2005; Gonner,

Leonhart, & Ecker, 2008; Smári, Ólason, Eypórsdóttir, & Frölunde, 2007; Tang, Yu, He, Wang,

Chasson, 2015; Zermatten, van der Linden, Jermann, & Ceschi, 2006; Woo, Kwon, Lim, & Shin,

2010). Of note, nearly half of the translated versions of OCI-R have been validated among non-

clinical populations (Fullana et al., 2005; Smari et al., 2007; Zermatten et al., 2006). Validating

OCI-R in community samples is important because the frequency of OCD-related behaviors is

considerably high in the general population. For instance, Fullana et al. (2010) found a lifetime

prevalence of 13% in any of the symptom categories that characterize OCD in the general

population. Research evidence also suggests that non-clinical participants, who self-report high

scores in obsessive-compulsive inventories, tend to produce stable obsessive-compulsive behaviors

across time, which closely correspond to those observed in clinical patients diagnosed with OCD

(Burns, Formea, Keortge, & Sternberger, 1995). Moreover, the use of a community sample

facilitates the investigation of the factor structure and the evaluation of the psychometric properties

of OCI-R (e.g., Sica et al., 2009).

Among the limitations of OCI-R’s scale is that its discriminant validity is only adequate to

good, likely because OCD usually co-exists with other disorders, with major depression possessing

a significant place among Axis I comorbid conditions commonly diagnosed with OCD (e.g.,

Abramowitz & Deacon, 2006; Foa et al., 2002; Tükel, Polat, Özdemir, Aksüt, & Türksoy, 2002).

Further, order effects have been observed when it is administered after another measure of OCD

(Hajcak et al., 2004; Woo et al., 2010). Gender effects also have been found in some cultural

settings. For instance, Spanish men have been found to have more hoarding and checking

complaints than Spanish women (Fullana et al., 2005), whereas Italian men score higher on

washing, checking and obsessing sub-scales than women of the same culture (Sica et al., 2009). In

Iceland, these findings are reversed with women reporting more complaints on the checking and

ordering sub-scales compared to men (Smári et al., 2007).

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A Greek version of the OCI-R does not exist. This is an important gap in the literature that

needs to be addressed for both research and clinical reasons. In terms of research, a Greek version

of the OCI-R would facilitate the research process and the direct comparison of studies focusing on

OCD in the Greek settings with studies conducted in other European or US settings. Clinically,

there is evidence that the frequency of OCD-related behaviors is considerably higher in Greek

samples compared to samples from other cultures. For instance, the mean score of the Hellenic

version of Spence Children’s Anxiety Scale (SCAS-GR; Mellon & Moutavelis, 2007) measuring

compulsive behavior in children aged from 9 to 12 years old was 82% higher compared to the mean

of the original scale (Spence, 1997), which was comprised of Australian children of the same age.

To date, there is no evidence with regard to the frequency of occurrence of OCD symptoms

in a Greek adult community sample, most probably due to the absence of a validated self-report

measure of OCD in Greece. Given the necessity of the existence of such an instrument, which

would reliably assess the frequency of OCD symptoms, an effort has been undertaken to translate

and validate OCI-R in the Greek context. The overarching aim of the present study was (a) to

evaluate the factor structure and the psychometric properties of the Greek-version of OCI-R in a

large community sample, (b) to overcome its previous limitations (e.g., discriminant validity) by

applying traditional and alternative validating methods, and (c) to test different structural models

according to the new research findings. Last, in view of the inconsistent findings that have been

produced with regard to the existence of both gender and order effects in other cultural settings

(Fullana et al., 2005; Hajcak et al., 2004; Sica et al., 2009, Smári et al., 2007; Woo et al., 2010), the

potential influence of gender differences and order effects on the administration of the Greek

version of OCI-R also was examined.

Method

Participants

In total, 1379 participants from the general community (31% males and 69% females) aged

from 18 to 83 years old (M = 27.54, SD = 10.76) completed the OCI-R scale. Potential participants

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had to satisfy the following criteria to be included in the study: (a) speak Greek fluently, and (b) be

Greek residents/citizens. Participation was voluntarily for all participants and informed consent was

obtained prior to scale completion. Approximately less than half of the participants (44%) were

university students, whereas 33.2% of the remaining participants had received university education

(e.g., first degree or master’s level). Only 5.6% of the study sample was unemployed and only 2%

had retired. With regard to the socio-economic status (SES), 24.8% of the study sample declared an

average household income of 600 euros per month (low SES), 46.6% declared a monthly income

ranging from 1200 to 2100 (middle SES), whereas the rest 28.6% of the sample declared making

more than 2100 euros per month (high SES). Fewer participants completed the total study measures

as detailed in Tables 6 and 7. No payments or course credits were offered for their participation.

Measures

Obsessive-compulsive inventory-revised (OCI-R) (Foa et al., 2002)

OCI-R consists of 18 items that measure distress caused by OCD symptoms. Participants’

scores are rated in a 5-point scale ranging from 0 = never to 4 = very much. OCI-R also consists of

six sub-scales, including washing, checking, orderliness, hoarding, neutralization and obsessions. In

the current study a Greek version of the OCI-R was used. The scale was translated from English to

Greek and back to English by six independent raters (three raters translated the scale from Greek to

English and the other three translated it from English to Greek). The accuracy of these translations

was reviewed by the authors of the study (IA, MP). In this study, the alpha coefficient was 0.89 for

the overall scale (see, Table 2). The final version of the Greek version of the scale is presented in

Appendix.

Maudsley obsessive-compulsive inventory (MOCI) (Hodgson & Rachman, 1977)

MOCI consists of 30 true-false statements that assess the frequency of OCD symptoms. It

covers four areas of complaints, that is, checking, cleanliness, slowness and doubting. MOCI has

good internal consistency and good to very good test-retest reliability and convergent validity

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(Emmelkamp, Kraaijkamp, & Van den Hout, 1999; Stoylen, Larsen, & Kvale, 2000). The alpha

coefficient for this scale was found to be very good, Cronbach’s α = 0.81, whereas the 30-day test-

retest reliability was excellent (0.83) in this study, suggesting proper psychometric qualities

(McCrae, Kurtz, Yamagata, & Terracciano, 2011).

Launay-Slade hallucinations scale (LSHS) (Launay & Slade, 1981)

LSHS is a 16-item self-report questionnaire that measures healthy individuals’

predisposition towards hallucinations. Responses are recorded in a 4-point scale, which range from

1 = never to 4 = very frequently. It incorporates three types of hallucinations, namely, intrusive

mental events, auditory religious and visual religious hallucinations. In this dataset, LSHS was

found to have excellent internal consistency, Cronbach’s a = 0.88, and an excellent 30-day test-

retest reliability (0.82), suggesting appropriate psychometric properties (McCrae, Kurtz, Yamagata,

& Terracciano, 2011).

Centre for epidemiological studies depression scale (CES-D) (Radloff, 1977)

CES-D consists of 20 items that measure the severity of depressive symptoms in the general

population. Participants self-report their answers in a 4-point scale by marking the number that

better describe their mood or feelings during the past week. CES-D scores range from 0 = rarely to

3 = most of the times. It has been found to have very good to excellent psychometric properties

(Fountoulakis et al., 2001). In the current study, the alpha coefficient was high, Cronbach’s a =

0.86, and the 1-month test-retest reliability was excellent (0.83).

Procedure

The first author, who had a first degree in Psychology and a postgraduate professional

qualification in Psychology, together with undergraduate Psychology students from Panteion

University, approached prospective participants. The majority of the student population was

comprised of participants mainly from Panteion University or National & Kapodistian University of

Athens. The non-student population was recruited from local coffee shops, cinemas and other

merchants. The first author and research assistants visited these establishments and recruited

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participants by asking customers if they would like to complete the survey. Those that agreed were

given a written consent form that informed them of the voluntary nature of the study. If they signed

the form, they were then taken to a quiet area of the establishment to complete the survey. After the

completion of the survey, participants were verbally debriefed regarding the aims of the study using

a script, so that debriefing statements were consistent across researchers. Data on a number of key

demographic characteristics (i.e., age, gender, occupation, socio-economic status) also were

recorded. Completion of these measures lasted approximately 20 min. To examine test-retest

reliability, the OCI-R was distributed again to 108 participants (56.5% of the sample was comprised

of undergraduate students) 30 days after its initial administration.

Data analyses

All statistical analyses were conducted using the IBM SPSS® (version 23.0) or the AMOS®

(version 23.0) statistical software. Study’s variables were tested for normality by assessing the

measure of skewness for every item, which revealed no deviation from a normal distribution. In the

current analysis both an explanatory factor analysis (EFA) and a confirmatory factor analysis (CFA)

were utilized. This decision was based on three reasons: (a) the symptoms that describe a number of

mental health disorders are possible to differ at least slightly among different cultural contexts, (b)

this is the first attempt to adapt the OCI-R in a Greek setting and therefore it is critical to explore

the structure of the Greek-version of the OCI-R (e.g., Gerbing & Hamilton, 1996), and (c) the mean

scores of the overall scale and the sub-scales of OCI-R were found to be exceptionally high, nearly

approaching the mean scores of the original study for the patient population sample. EFA also is

more appropriate for appraising the factor structure of an instrument, which has been in an initial

stage of development or validation within a particular cultural setting, and reducing multiple

observed variables into fewer components that summarize their variance (see, Byrne, 2001). To this

end, an EFA with promax rotation was employed, because the factors of the scale correlated

significantly with one another, together with a CFA. For the CFA, the maximum likelihood

estimation method was used. We tested the fit of the overall scale, a five-factor model by omitting

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the hoarding sub-scale in accordance with the new recommendations and a six-factor model that

have been proposed by the vast majority of the studies validating OCI-R in either clinical or

community samples across different social settings. Test-retest reliability was assessed by

producing Pearson product-moment correlation coefficients from Time 1 (initial administration) to

Time 2 (30 days later) administrations of the scale. Pearson’s r coefficients also were produced to

examine the inter-factor correlations of the OCI-R and to assess the convergent and discriminant

validity of the scale. In addition, we explored convergent validity by computing Average Variance

Extracted (AVE) scores, discriminant validity by producing square roots for AVE, and the internal

consistency by calculating Composite Reliability (CR) scores for each of the suggested factors of

the model. Independent-samples t-tests were conducted to explore potential gender differences on

the scores of OCI-R for the total, non-college and the college study’s samples and to examine the

possibility of an order effect.

Missing values

Initial screening revealed 76 cases with missing values in the OCI-R and in additional study

measures. A non-significant Little’s MCAR test, x2(220) = 208.09, p = 0.71, suggested data missing

completely at random (Little, 1988). To this end, single imputation methods using maximization

expectation algorithm were performed (Scheffer, 2002). The imputed scores were used for both the

EFA and CFA analyses. Then, we repeated all factor analyses to ensure that our findings remained

unchanged and unbiased. With regard to subsequent analyses (e.g., correlations) and in line with

recommendations (e.g., Rubin, 1987), we performed multiple imputations analyses. These scores

entered the final analyses. Again, in order to ensure that our interpretation was not biased, we

performed all the analyses with and without the imputed values.

Results

Descriptive statistics

The means and standard deviations of the OCI-R across the male and female participants of

the total, non-college and college study samples are detailed in Table 1. In general, the overall mean

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of the OCI-R of the current study (M = 26.82, SD = 12.79) closely resembled the overall mean

reported for the patient population (M = 28.01, SD = 13.52), but not for the non-anxious controls

(M = 18.82, SD = 11.10) of the original study (Foa et al., 2002). A number of additional differences

also were found. For example, higher means in the ordering (M = 5.96, SD = 3.24) and hoarding

sub-scales (M = 4.75, SD = 2.96), but lower means in the obsessing (M = 5.13, SD = 3.24),

neutralizing (M = 2.51, SD = 2.63) and washing sub-scales (M = 3.72, SD = 3.11) were reported in

this sample compared to the patient one of the original OCI-R version. The mean of the checking

sub-scale (M = 4.73, SD = 3.32) was found to be similar to the one reported by Foa et al. (2002).

On average, females of the total study sample self-reported more obsessions (M = 5.32, SE =

0.14) than males (M = 4.76, SE = 0.21), t(1377) = -3.37, p < 0.001, d = 0.20. Overall, females of the

non-college sample reported more obsessive-compulsive symptoms (M = 28.55, SE = 0.57) than

males (M = 26.10, SE = 0.82), t(770) = -2.41, p < 0.05, d = .19, more washing (M = 4.15, SE =

0.14) than males (M = 3.66, SE = 0.20), t(770) = -1.98, p < 0.05, d = 0.16, more obsessions (M =

5.32, SE = 0.14) than males (M = 4.76, SE = 0.21), t(770) = -2.22, p < 0.05, d = 0.17, and more

ordering concerns (M = 6.50, SE = 0.14) than males (M = 5.32, SE = 0.22), t(707) = -2.81, p < 0.05,

d = 0.20. With regard to the college study sample, we found that on average men self-reported more

neutralizing (M = 2.82, SE = 0.22) than women (M = 2.18, SE = 0.12), t(605) = 2.81, p < 0.05, d =

0. 23. Females reported, on average, more obsessions (M = 5.33, SE = 0.16) than men (M = 4.61,

SE = 0.22), t(605) = -2.57, p < 0.05, d = 0. 22. Although statistically significant, the aforementioned

differences between males and females are translated into minimal or small effect sizes.

[Table 1 about here]

Factor structure of the scale

An EFA was conducted on the 18 items with the promax rotation method due to the strong

inter-factor correlations. The Kaiser-Meyer-Olkin measurement confirmed that the sample size was

adequate to perform such an analysis, KMO = 0.87 and the KMO values for all items separately

were > 0.66, above the recommended value of 0.6. Bartlett’s test of sphericity x2 (153) = 10212.420,

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p < 0.001, indicated that the correlations between the items were sufficiently large to perform this

analysis. Initially, a first analysis produced six independent factors based on the eigenvalues, which

exceeded the Kaiser criterion (which is 1) and in combination explained 70.29% of the total

variance. The scree plot also supported the six-factor solution for this scale based on the

eigenvalues. Table 2 presents the factor loadings of the OCI-R scale after performing a promax

rotation, together with the eigenvalues, the percentage of variance accounted for and the Cronbach’s

alphas for each of the extracted factors. The items concentrated around the same components

suggest that factor 1 represents checking, factor 2 ordering, factor 3 obsessing, factor 4 hoarding,

factor 5 washing and factor 6 neutralizing.

[Table 2 about here]

Construct validity

A CFA was conducted to evaluate the fit of the data to the six-factor structure solution that

was initially suggested by the original OCI-R scale development and also confirmed in this study by

performing an EFA. The model had a significant Chi-square, x2(120) = 555.71, x2/d.f. = 4.63, p <

0.001, which is explained by the utilization of a large dataset and therefore must be ignored

(Jöreskog & Sörbom, 1993). As detailed in Table 3, the goodness-of-fit indices indicated that the

six-structure model of the Greek version of OCI-R was supported. In particular, the model had a

Goodness-of-Fit Index (GFI) of 0.96, a Comparative Fit Index (CFI) of 0.96, a root-mean-square

residual (RMR) of 0.06, and a root-mean-square error of approximation (RMSEA) of 0.05 (for

cutoff criteria for fit indexes see, Hu & Bentler, 1999). We also examined a five-factor model by

excluding the hoarding sub-scale. This model had a significant Chi-square, x2(80) = 355.85, x2/d.f. =

4.44, p < 0.001, a Goodness-of-Fit Index (GFI) of 0.97, a Comparative Fit Index (CFI) of 0.97, a

root-mean-square residual (RMR) of 0.05, and a root-mean-square error of approximation

(RMSEA) of 0.05, indicating a slightly better conceptual fit of the data. A one-factor model also

was tested but data clearly failed to fit this model.

[Table 3 about here]

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Congruence coefficients

Tucker’s congruence coefficients were calculated as an index of similarity between the

original and the Greek version of OCI-R factor loadings as were detected in Foa’s et al. (2002) and

the current study’s datasets. As shown in Table 4, a high degree of factor similarity was observed

among all the six factors as were proposed by the original study and replicated in the Greek context,

with rc ranging from 0.82 to 0.89.

[Table 4 about here]

Internal consistency of the overall scale and its sub-scales

Cronbach’s coefficients were calculated for all the six constructs as shown in Table 2. All

but the neutralizing construct showed an internal consistency higher than the recommended value

(alpha < 0.70). The alpha coefficient was 0.89 for the overall OCI-R. We also examined composite

reliability (CR) by calculating CR indexes for each of the constructs. CRs were exceeded the

recommended value of 0.06 for all the six sub-scales.

Test-retest reliability

Pearson’s correlation coefficients were calculated to assess test-retest reliability for OCI-R

as shown in Table 5. Overall, the test-retest reliability for the total scale and the sub-scales was very

good to excellent, ranging from 0.70 to 0.81. The test-retest for the total OCI-R was found to be

excellent (r = 0.81) in a one-month period. The hoarding (r = 0.70), neutralizing (r = 0.71) and

obsessing (r = 0.74) sub-scales showed the lowest test-retest reliabilities, whereas the ordering (r =

0.77), the washing (r = 0.79) and the checking (r = 0.81) sub-scales showed an excellent one-month

test-retest reliability.

[Table 5 about here]

Inter-correlations between OCI-R and its sub-scales

As detailed in Table 6, the overall OCI-R was strongly correlated with all the sub-scales (r

ranges from 0.59 to 0.75) indicating that the six factors together with the overall scale represent the

same theoretical concept (e.g., symptoms of OCD). The inter-correlations among the sub-scales

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ranged from 0.22 to 0.52 suggesting a sufficient but not satisfactory relationship among the

different sub-scales of the OCI-R, which supports further the existence of multidimensionality in

OCD.

[Table 6 about here]

Convergent validity

As shown in Table 7, the correlation of the overall OCI-R with the overall MOCI was high

(r = 0.67), indicating a very good convergent validity. MOCI also correlated highly with the

washing (r = 0.56) and the checking (r = 0.55) sub-scales of OCI-R. The obsessing (r = 0.49),

ordering (r = 0.45) and neutralizing (r = 0.42) scales also were satisfactorily correlated with MOCI,

whereas the hoarding scale (r = 0.31) showed the lowest correlation with the overall MOCI. The

checking sub-scale of OCI-R correlated highly with the checking sub-scale of MOCI, (r = 0.57) and

the washing sub-scale of OCI-R also correlated highly with the cleaning sub-scale of MOCI, (r =

0.53). Further, the calculations of the AVE indexes verified that convergent validity was achieved

because all indexes were 0.5 or higher.

[Table 7 about here]

Discriminant validity

The Pearson’s correlation coefficients between the total OCI-R and its sub-scales with the

CES-D and LSHS are presented at Table 8. The results indicated moderate correlations between the

OCI-R with both the CES-D and LSHS (r = 0.47 and r = 0.47 respectively). The obsessing scale

correlated moderately with CES-D (r = 0.39), whereas the rest sub-scales of OCI-R were correlated

only moderately to weakly with the CES-D, ranging from r = 0.31 to r = 0.33. The obsessing scale

was correlated moderately with the LSHS (r = 0.42), whereas moderate or weak correlations were

found between the LSHS and the other sub-scales of the OCI-R, ranging from r = 0.24 to r = 0.39.

Table 6 also presents the square roots of AVE indexes for all the six constructs. These results

indicate that discriminant validity was achieved because all indexes (diagonal values in bold) were

found to be higher than the values in their rows and columns. Further, none of these indexes

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exceeded the critical value of 0.85, which suggests the existence of a redundant factor or serious

multicollinearity problems.

[Table 8 about here]

Order effects

On average, participants tended to score higher on OCI-R when it was administered after

MOCI (M = 27.74, SE = 0.53) than when it was administered first (M = 26.04, SE = 0.50), t(1377) =

2.33, p > 0.05, d = 0.13. However, these differences represented only minimal effect sizes.

Discussion

The current study evaluated the psychometric properties of a Greek version of OCI-R in a

large community sample. The results clearly demonstrated that the Greek version of OCI-R has

excellent psychometric properties. A core strength of this study is that we utilized a large non-

clinical population comprised of both university students and individuals from the community.

In accordance with the original version of the OCI-R and other translated versions, the

factor structure of the scale yielded six independent factors, namely, checking, ordering, obsessing,

hoarding, washing and neutralizing, conforming to the six factor solution of the original scale

(Aydin et al., 2014; Gonner et al., 2008; Foa et al., 2002; Fullana et al., 2005; Smári et al., 2007;

Zermatten et al., 2006; Woo et al., 2010). A CFA also suggested an excellent fit for the six-factor

solution, whereas Tucker’s correlation coefficients also confirmed the existence of a high degree of

factor similarity between the original and Greek factors of the OCI-R scale. Given the current

changes in the DSM-5, where hoarding symptoms compose a whole new disorder, we also tested a

five model fit by omitting the hoarding sub-scale. This model was found to be slightly superior to

the original six-model structure of the OCI-R. Therefore, in line with recent evidence (Wootton

Diefenbach, Bragdon, Steketee, Frost, & Tolin, 2015), we recommend that the five-scale of OCI-R

can be used reliably. Finally, we tested the model fit for the overall scale, but clearly CFA failed to

support a one-factor solution for the OCI-R scale, supporting, thus, the heterogeneity of the

symptoms characterizing OCD.

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With regard to the internal consistency, it was found to be excellent for the overall scale and

very good to excellent for five of the sub-scales. Only the neutralizing sub-scale showed an internal

consistency lower than the recommended value (alpha < .70; see, Nunnally, & Bernstein, 1994).

However, this result is consistent with the findings of the vast majority of the studies that adapted

OCI-R in different cultural settings or populations (Aydin et al., 2014; Hajack et al., 2005; Fullana

et al., 2005; Smári et al, 2007; Zermatten et al., 2006; Woo et al., 2010). The low internal

consistency of the neutralizing sub-scale likely results from the fact that two of the sub-scales’

items focus primarily on counting behaviors, whilst another item focuses on assessing superstitious

cognitions. We tested this possibility by computing composite validity indexes, which have been

suggested to be superior to alpha coefficient when testing sub-scales (Raykov, 1998). CRs

confirmed the existence of a high internal consistency for all the sub-scales, suggesting that the sub-

scales’ items hold strong together in measuring the same constructs.

All, but the hoarding sub-scale, correlated strongly with the overall OCI-R. This finding

suggests that all the sub-scales, but the hoarding, can reliably differentiate participants who self-

report symptoms of OCD from participants who do not report such symptoms (e.g., Mataix-Cols et

al., 2005). A low correlation between the hoarding sub-scale and the overall OCI-R has been

reported repeatedly in the literature (e.g., Foa et al., 2002; Woo et al., 2002), suggesting that

hoarding may not be a fully representative feature of this disorder (Grisham & Norberg, 2010;

Mataix-Cols et al, 2010; Steketee & Frost, 2003). Indeed, in DSM-5, hoarding is not anymore listed

as a criterion for the diagnosis of OCD, but rather comprises a distinct disorder, which is classified

under the obsessive-compulsive and related disorders chapter (APA, 2013). Further, data of a recent

study suggested that the OCI-R’s three-item hoarding sub-scale can reliably differentiate between

hoarders and non-hoarders (Wootton et al., 2015).

The convergent validity between the OCI-R with the MOCI was strong, confirming that

OCI-R has been developed to measure symptoms that indicate OCD. Similar findings have been

reported by Hajcak et al. (2004) and Smári et al. (2007), who also found strong associations

16

between the total OCI-R and MOCI (r = 0.67 and r = 0.60 respectively). Although Foa et al. (2002)

reported a much higher correlation between OCI-R and MOCI (r = 0.85), variations in sample used

across studies might account for this difference. Indeed, Foa et al. (2002) utilized a clinical sample,

while this study was based on a community sample. Consistent with this explanation, two other

studies, which used community samples, reported similar correlations between OCI-R and MOCI to

the ones reported in the current study (see, Hajcak et al., 2004; Smári et al., 2007). We also

produced AVE scores, which fully supported that the Greek version of OCI-R achieved convergent

validity. We highly recommend that future studies calculate such scores, especially in cases where

there is ambiguity with regard to the validity of a measure.

Consistent with the evidence suggesting that OCD has common features with depression and

hallucinations (e.g., Guillem, Satterthwaite, Pampoulova, & Stip, 2009; Nestadt et al., 2001; Shioiri,

Shinada, Kuwabara, & Someya, 2007), we anticipated that a moderate association between OCI-R

and CES-D or LSHS would be a good estimate of OCI-R’s discriminant validity. Indeed, OCI-R

was moderately associated with both the CES-D and LSHS scales indicating adequate discriminant

validity. In accordance with our results, the vast majority of the studies that have validated OCI-R

in other cultural settings or re-examined OCI-R’s psychometric properties have reported the

existence of a good or adequate discriminant validity (Hajcak et al., 2004; Fullana et al., 2005; Sica

et al., 2009; Smári et al., 2007; Woo et al., 2010), including the original development study (Foa et

al., 2002), likely due to the high comorbidity between the diagnosis of OCD and other Axis I

disorders, especially major depression (Abramowitz & Deacon, 2006; Tükel et al., 2002). We tested

this possibility by producing squares roots of AVE scores. Clearly, our analyses supported the

discriminant validity for this scale.

Of note, the total OCI-R yielded a mean score almost as high as the one reported by Foa et

al. (2002) despite the fact that the original study was based on a clinical population. Consistent with

this finding, the Greek version of the OCI-R showed the highest one-month test-retest reliability

that has been reported in the literature that closely resembled the findings of the original scale in the

17

patient population (Foa et al., 2002). This finding suggests that the exceptionally high mean scores

of OCD symptoms found in the Greek community sample remain stable over time. It is interesting

to note that Fountoukakis et al. (2001), who validated a Greek version of the CES-D, reported no

mean differences between depressed patients and healthy controls, suggesting that the symptoms

that characterize depression were significantly elevated in Greek populations. Further, Mellon

(2000) found that self-reported fears were considerably higher in Greek children and adults

compared to other cultures. Coercive parenting and educational practices, together with adverse

social interactions, have been reported to play a role in the development of both OCD and

depressive features in American study samples (e.g., Afifi, Mota, Dasiewicz, MacMillan, & Sareen,

2012), so it is possible that these may be the critical factors in explaining the prevalence of OCD

and depression in Greece. Previous studies conducted in Greece (e.g., Mellon, 2000; Mellon &

Moutavelis, 2007) reported that among the crucial factors that differentiate the Greek culture from

other Mediterranean or European cultures are child-rearing practices that bring specific attention to

the dangers that exist outside the safety of one’s home. Further, the Greek educational system has

been characterized as harsh and punitive, which may contribute to the development of compulsive

and related behaviors to avoid and/or escape the anxiety generated by such pedagogic practices.

However, further research will be needed to replicate the outcomes of the current study and to

examine the underlying mechanisms that account for the high prevalence of OCD and other Axis I

disorders in the Greek community. We believe our findings will serve as an important basis for that

research.

No considerable gender differences were found in the total OCI-R. However, women of

both the total and the non-college samples tended to report more frequent obsessions than men, a

finding which was translated into small effect sizes. Further, women of the non-college sample

reported more concerns with washing and ordering compared to men, but the effect sizes of these

differences were only small. Conversely, men of the college sample tended to report neutralizing

more often compared to women, but this difference was translated into a small effect size. Overall

18

and consistent with the extant literature, no considerable differences have been reported between

men and women with regard to self-reporting OCD symptoms across different cultures.

OCI-R produced slightly higher overall scores, when followed MOCI. Although, Foa et al.

(2002) and Woo et al. (2008) reported a slight decrease on the scores of the overall OCI-R when it

followed another obsessive-compulsive scale, we found the opposite pattern of results. One

plausible explanation is that a repetitious examination of the OCD symptoms might increase

participants’ awareness with regard to the purposes of the study. However, following calculation of

the effect sizes we found that clinical significances of these results are only minimal.

Strengths & limitations

This study has several strengths. Given the necessity for the existence of a validated scale,

our analysis confirmed that the Greek version of OCI-R is a sound psychometric tool for assessing

symptoms of OCD in the Greek context. This study utilized both classical (e.g., based on EFA and

Cronbach’s alpha) and modern (e.g., based on structural equation modelling) methods for

evaluating the psychometric properties of the Greek OCI-R. By doing this, we overcame previous

limitations that suggested OCI-R to have only adequate discriminant validity, or poor internal

consistency for the neutralizing sub-scale. Further, to the best of our knowledge, this is the first

study that demonstrated that a five-factor model provided a slightly better conceptually fit of the

data conforming thus to the latest findings and revisions of the DSM-V. Last, we demonstrated that

the use of contemporary validating methods, even if they are more conservative, can overcome

limitations inherited in the classical methods (e.g., Bagozzi, Yi, & Phillips, 1991). Therefore, we

encourage future researchers to apply these techniques alone or in combination with more

traditional ones.

Despite its strengths, some limitations should be noted. First, despite the utilization of a

large study sample, no participants with a clinical diagnosis of OCD were included in this study.

Although OCI-R was developed for use in both clinical and non-clinical populations, it would be

interesting to re-examine the psychometric properties of OCI-R in patients who have received a

19

clinical diagnosis of OCD. Second, although the mean scores of the OCI-R was found to be much

higher in a Greek sample compared to those reported in other countries, a finding that is consistent

with the mean scores found in the Greek versions of similar scales measuring symptoms of

depression, anxiety, and fears, the reasons of this variation are unknown and remain to be explored

by future studies. Third, more than two-thirds of the participants were females, which might have

obscured the effect sizes of the differences detected between the males and females. Lastly, the vast

majority of the participants had received university education; therefore, the results might not

necessarily be representative of people with no or little education.

Compliance with Ethical Standards

Role of funding sources: No financial support has been received.

Conflict of interest: All authors declare no conflict of interest.

Ethical approval: All procedures performed in this study were in accordance with the ethical

standards of the institutional and/or national research committee and with the 1964 Helsinki

declaration and its later amendments or comparable ethical standards.

Informed consent: Informed consent was obtained from all individual participants included in the

study.

20

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Table 1Means and standard deviations of the overall OCI-R and its sub-scales for the total and college sample

Checking Ordering Obsessing Hoarding Washing Neutralizing OCI-R

M SD M SD M SD M SD M SD M SD M SD N % t✝ P value

Total sample

Men 4.62 3.39 5.72 3.21 4.69** 3.11 4.52 2.90 3.54 3.02 2.80 2.72 25.72 12.53 428 31.04

Women 4.78 3.29 6.07 3.25 5.32** 3.27 4.85 2.98 3.88 3.14 2.38 2.58 27.31 12.88 951 68.46

Total 4.73 3.32 5.96 3.24 5.13 3.24 4.75 2.96 3.72 3.11 2.51 2.63 26.82 12.79 1379 100 -2.15 0.03

Non-college sample

Men 4.77 3.44 5.85* 3.39 4.76* 3.14 4.54 3.01 3.66 3.12* 2.78 2.47 26.10 12.54 232 16.82

Women 5.09 3.35 6.50* 3.21 5.32* 3.27 4.87 3.09 4.14 3.19* 2.53 2.65 28.55 13.13 540 39.16

Total 4.99 3.37 6.30 3.26 5.16 3.24 4.78 3.07 4.00 3.17 2.61 2.60 27.81 13.00 772 55.98 -2.41 0.02

College sample

Men 4.44 3.34 5.56 2.99 4.61* 3.09 4.50 2.78 3.40 2.91 2.67* 2.76 25.26 12.53 196 14.21

Women 4.37 3.16 5.50 3.22 5.33* 3.29 4.82 2.82 3.52 3.06 2.82* 3.00 25.68 12.38 411 29.81

Total 4.39 3.22 5.52 3.15 5.09 3.24 4.72 2.81 3.48 3.01 2.18 2.47 25.55 12.42 607 44.02 -.39 0.70

Note. OCI-R = Obsessive Compulsive Inventory - Revised.* Statistical significant differences between males and females, p < 0.01** Statistical significant differences between males and females, p < 0.001 ✝ t-scores were calculated on the overall OCI-R between males and females for the total, non-college and college sample.

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Table 2Summary of exploratory factor analysis results from the OCI-R (N = 1379)

Rotated Factor Loadings

Items Checking Ordering Obsessing Hoarding Washing Neutralizing

14 0.91 -0.04 0.06 -0.05 0.02 -0.01

8 0.88 -0.01 -0.01 0.02 0.08 -0.05

2 0.82 0.05 -0.04 0.06 -0.08 0.06

15 -0.05 0.86 -0.04 -0.05 0.03 0.06

3 0.11 0.85 0.00 -0.06 -0.08 -0.01

9 -0.12 0.81 0.05 0.10 0.08 -0.07

18 0.03 -0.01 0.88 0.00 -0.01 0.06

12 -0.01 0.11 0.83 -0.01 0.00 0.02

6 0.00 -0.07 0.81 0.03 -0.04 -0.06

7 -0.03 -0.06 0.01 0.89 0.01 -0.01

1 0.03 -0.05 -0.05 0.77 -0.07 0.06

13 0.03 0.01 0.08 0.77 0.08 -0.05

11 -0.08 -0.01 0.07 0.01 0.87 -0.01

5 0.02 0.01 -0.16 0.03 0.86 0.02

17 0.13 0.04 0.07 -0.05 0.71 0.03

10 0.00 -0.07 0.03 0.00 0.01 0.85

16 -0.06 -0.07 0.05 -0.05 0.10 0.78

4 0.05 0.16 -0.09 0.08 -0.08 0.69

Eigenvalues 6.17 1.85 1.30 1.18 1.14 1.03

% of variance 34.27 10.28 7.21 6.57 6.33 5.60

a 0.84 0.79 0.80 0.76 0.78 0.67

Note: Factor loadings over 0.60 appear in bold.

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Table 3 Goodness-of-Fit Indicators of the Greek version of OCI-R (N = 1379)

Model X2* df x2/df GFI CFI RMR RMSEA

One-Factor 4010.78 135 29.71 0.74 0.62 0.15 0.14

Five-Factor 355.85 80 4.44 0.97 0.97 0.05 0.05

Six-Factor 555.71 120 4.63 0.96 0.96 0.06 0.05

Note. *p <0.001.

Table 4 Tucker’s coefficient of congruence between factor loadings for the OCI-R from the Greek and Foa’s et al. (2002) dataset

1 2 3 4 5 6

Checking 0.88

Ordering 0.87

Obsessing 0.87

Hoarding 0.85

Washing 0.86

Neutralizing 0.82

Note. OCI-R = Obsessive Compulsive Inventory - Revised.

Table 5Test-retest reliability for overall OCI-R and its sub-scales (Ν = 108)

Pearson’sCorrelation

Coefficient (r)

Checking 0.81

Ordering 0.77

Obsessing 0.74

Hoarding 0.70

Washing 0.79

Neutralizing 0.71

OCI-R 0.81

Note: All correlations are significant in level p < 0.001, OCI-R = Obsessive Compulsive Inventory-Revised, Ν = Total number of participants.

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Table 6Square root of AVE and pearson inter-correlations between the overall OCI-R scale and its sub-scales (Ν = 1379)

1 2 3 4 5 6 OCI-R

Checking 0.81 0.75

Ordering 0.48 0.77 0.71

Obsessing 0.38 0.34 0.78 0.70

Hoarding 0.34 0.22 0.40 0.72 0.59

Washing 0.52 0.47 0.42 0.27 0.74 0.73

Neutralizing 0.42 0.39 0.35 0.29 0.42 0.69 0.67

Note: All correlations are significant in level p < 0.001, OCI-R = Obsessive Compulsive Inventory-Revised, Ν = Total number of participants.

Table 7Convergent validity of the OCI-R and its sub-scales with MOCI and its sub-scales, AVE and CR indexes* (Ν = 1052)

Checking Cleaning MOCI AVE* CR*

Checking 0.57 0.34 0.55 0.66 0.93

Ordering 0.38 0.35 0.45 0.58 0.91

Obsessing 0.52 0.27 0.49 0.60 0.92

Hoarding 0.33 0.17 0.31 0.52 0.89

Washing 0.46 0.53 0.56 0.54 0.89

Neutralizing 0.41 0.21 0.42 0.51 0.87

OCI-R 0.65 0.44 0.67 - -

Note: All correlations are significant in level p < 0.001, OCI-R = Obsessive Compulsive Inventory-Revised, MOCI = Maudsley Obsessive Compulsive Inventory.* AVE & CR indexes were calculated utilizing the entire study sample, N = 1379

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Table 8Discriminant validity of the OCI-R with CES-D and LSHS (Ν = 1052)

CES-D LSHS

Checking 0.33 0.28

Ordering 0.33 0.24

Obsessing 0.39 0.42

Hoarding 0.31 0.31

Washing 0.32 0.35

Neutralizing 0.31 0.39

OCI-R 0.47 0.47

Note: All correlations are significant in level p < 0.001, OCI-R = Obsessive Compulsive Inventory-Revised, CES-D = Centre for Epidemiological Studies Depression Scale, LSHS = Launay-Slade Hallucinations Scale.

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Appendix A

The Greek version of the OCI-R

The following statements refer to experiences that many people have in their everyday lives. Circle the number that best describes HOW MUCH that experience has DISTRESSED or BOTHERED you during the PAST MONTH. The numbers refer to the following verbal labels

Οι παρακάτω προτάσεις αναφέρονται σε εμπειρίες που πολλοί άνθρωποι έχουν στην καθημερινή ζωή. Κυκλώστε τον αριθμό που περιγράφει καλύτερα το ΠΟΣΟ ΠΟΛΥ αυτή η εμπειρία σας έχει ΣΤΕΝΑΧΩΡΗΣΕΙ ή ΕΝΟΧΛΗΣΕΙ κατά τη διάρκεια του προηγούμενου μήνα. Οι αριθμοί αναφέρονται στις παρακάτω λεκτικές σημασίες: 0 1 2 3 4

Not at allΚαθόλου

A littleΛίγο

ModerartelyΜέτρια

A lotΠολύ

ExtremelyΠάρα πολύ

1. I have saved up so many things that they get in the way. Έχω φυλάξει τόσα πολλά πράγματα που με εμποδίζουν.

0 1 2 3 4

2. I check things more often than necessary. Ελέγχω τα πράγματα πιο συχνά από ότι είναι απαραίτητο.

0 1 2 3 4

3. I get upset if objects are not arranged properly. Αναστατώνομαι εάν τα πράγματα δεν είναι σωστά τακτοποιημένα.

0 1 2 3 4

4. I feel compelled to count while I am doing things. Νιώθω την ανάγκη να μετράω τη στιγμή που κάνω πράγματα.

0 1 2 3 4

5. I find it difficult to touch an object when I know it has been touched by strangers or certain people. Το βρίσκω δύσκολο να ακουμπήσω ένα αντικείμενο όταν ξέρω ότι το έχουν ακουμπήσει ξένοι ή ορισμένοι άνθρωποι.

0 1 2 3 4

6. I find it difficult to control my own thoughts. Το βρίσκω δύσκολο να ελέγχω τις δικές μου σκέψεις.

0 1 2 3 4

7. I collect things I don’t need. Συγκεντρώνω πράγματα που δε χρειάζομαι.

0 1 2 3 4

8. I repeatedly check doors, windows, drawers, etc.Ελέγχω επανειλημμένα πόρτες, παράθυρα, συρτάρια κτλ.

0 1 2 3 4

9. I get upset if others change the way I have arranged things. Αναστατώνομαι εάν οι άλλοι αλλάξουν τον τρόπο με τον οποίο έχω τακτοποιήσει τα πράγματα.

0 1 2 3 4

10. I feel I have to repeat certain numbers.Νιώθω ότι πρέπει να επαναλαμβάνω συγκεκριμένους αριθμούς.

0 1 2 3 4

11. I sometimes have to wash or clean myself simply because I feel 0 1 2 3 4

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contaminated. Μερικές φορές πρέπει να πλυθώ ή να καθαριστώ απλά επειδή νιώθω μολυσμένος.

12. I am upset by unpleasant thoughts that come into my mind against my will. Αναστατώνομαι από δυσάρεστες σκέψεις που έρχονται στο μυαλό μου παρά τη θέλησή μου.

0 1 2 3 4

13. I avoid throwing things away because I am afraid I might need them later. Αποφεύγω να πετάω πράγματα επειδή φοβάμαι ότι μπορεί να τα χρειαστώ αργότερα.

0 1 2 3 4

14. I repeatedly check gas and water taps and light switches after turning them off. Ελέγχω επανειλημμένα το μάτι της κουζίνας, το θερμοσίφωνα και τις βρύσες και τους διακόπτες του φωτός αφού τους έχω κλείσει.

0 1 2 3 4

15. I need things to be arranged in a particular order. Χρειάζομαι τα πράγματα να είναι τακτοποιημένα με συγκεκριμένη σειρά.

0 1 2 3 4

16. I feel that there are good and bad numbers. Πιστεύω ότι υπάρχουν καλοί και κακοί αριθμοί.

0 1 2 3 4

17. I wash my hands more often and longer than necessary. Πλένω τα χέρια μου πιο συχνά και για μεγαλύτερη διάρκεια από ότι είναι απαραίτητο.

0 1 2 3 4

18. I frequently get nasty thoughts and have difficulty in getting rid of them. Συχνά μου έρχονται κακές σκέψεις και έχω δυσκολία στο να απαλλαχτώ από αυτές.

0 1 2 3 4

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