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Anxiety Disorders 19 (2005) 893–903

Psychometric properties of the Spanish version of the Obsessive–Compulsive Inventory— Revised in a non-clinical sample Miquel A. Fullanaa,*, Miquel Tortella-Feliub, ´ scar Andio´na, Rafael Torrubiaa, Xavier Caserasa, O David Mataix-Colsc b

a Department of Psychiatry, Autonomous University of Barcelona, Catalonia, Spain Department of Psychology, University Research Institute on Health Sciences (IUNICS), University of the Balearic Islands, Majorca, Spain c Institute of Psychiatry, King’s College, London, UK

Received 8 June 2004; received in revised form 30 September 2004; accepted 25 October 2004

Abstract The psychometric properties of a Spanish version of the Obsessive–Compulsive Inventory—Revised (OCI-R) were examined in a non-clinical student sample (n = 381). A confirmatory factor analysis replicated the original six-factor structure. The total and each of the subscales of the Spanish OCI-R demonstrated moderate to good internal consistency and test-retest reliability, moderate convergent validity and good divergent validity. The Spanish version of the OCI-R retains the sound psychometric properties of the original version. # 2004 Elsevier Inc. All rights reserved. Keywords: Obsessive–compulsive disorder; Assessment; Symptom dimensions

1. Introduction Several self-report measures of obsessive–compulsive symptoms have been developed over the years (see Taylor, 1998, for a review). New self-report * Corresponding author. Tel.: +34 93 581 12 23; fax: + 34 93 581 14 35. E-mail address: [email protected] (M.A. Fullana). 0887-6185/$ – see front matter # 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.janxdis.2004.10.004

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M.A. Fullana et al. / Anxiety Disorders 19 (2005) 893–903

measures have recently been developed to overcome the limitations of their predecessors, particularly their insufficient coverage of all types of symptoms. These include the Padua Inventory (Sanavio, 1988) and its subsequent revisions (e.g. the Padua Inventory—Washington State University Revision, PI-WSUR; Burns, Keortge, Formea, & Sternberger, 1996); the Vancouver Obsessional Compulsive Inventory (Thordarson et al., 2004), a revision of the widely used Maudsley Obsesional Compulsive Inventory (MOCI; Hodgson & Rachman, 1977); and the Obsessive– Compulsive Inventory (OCI; Foa, Kozak, Salkovskis, Coles, & Amir, 1998). The OCI consists of 42 items grouped in seven subscales (checking, washing, obsessing, mental neutralizing, ordering, hoarding, and doubting) measured on two 5-point Likert scales of symptom frequency and associated distress. The OCI showed sound psychometric properties in both clinical (Foa et al., 1998) and nonclinical samples (Simonds, Thorpe, & Elliott, 2000; Wu & Watson, 2003). However, since frequency and distress scales of the questionnaire seemed redundant and in order to make the administration easier, a revised and shortened version was developed, the Obsessive–Compulsive Inventory—Revised (OCI-R; Foa et al., 2002). The OCI-R consists of 18 items and provides a total score and scores on six subscales: washing, checking, ordering, obsessing, hoarding, and neutralizing. The psychometric properties of the OCI-R were examined in a sample of 215 patients with OCD, 243 patients with other anxiety disorders, and 677 nonanxious individuals (Foa et al., 2002). The OCI-R had good or excellent internal consistency, test-retest reliability, and convergent validity. It also showed a good ability to discriminate between patients with OCD and other anxious groups, with the exception of its hoarding and ordering subscales. Recently, Hajcak, Huppert, Simons, and Foa (2004) have presented data of two studies which examined the psychometric properties of the OCI-R in a college sample. Their results confirmed the six-factor structure obtained by Foa et al. (2002) and indicated adequate test-retest reliability for the full scale and subscale scores, high internal consistency, and good convergent and divergent validity. The OCI-R seems therefore a promising instrument for the assessment of both clinical and non-clinical samples. However, its psychometric properties have not been examined independently by a group of investigators that did not develop the measure or in other cultural contexts. Although prevalence rates of OCD are remarkably consistent among different cultures, some variability in symptom presentations exists, which could be related to cultural factors (Weissman et al., 1994). The replication of research across different societies requires the use of instruments that have been standardized in those cultural contexts. Furthermore, practical reasons such as having usable clinical assessment techniques or the possibility of usage in multicenter treatment trials foster the cross-cultural adaptation of assessment instruments (Arrindell, de Vlaming, Eisenhardt, van Berkum, & Kwee, 2002). The main goal of this study was to provide the initial Spanish norms for the OCI-R and to examine its psychometric properties and factor structure in a sample


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of college students. We also wished to examine the possible sex differences in the OCI-R subscales, an issue that was not addressed in the previous reports (Foa et al., 2002; Hajcak et al., 2004). Although prevalence of OCD is similar in both genders, according to some clinical data the frequency of particular obsessive–compulsive symptoms may be different in men and women, with men showing more symmetry, order, and hoarding symptoms and women displaying more contamination and washing symptoms (e.g., Lensi, Cassano, Correddu, Ravagli, & Kunovac, 1996; Noshirvani, Kavsikis, Marks, Tsakiris, & Monteiro, 1991; Samuels et al., 2002). In non-clinical samples, gender differences have emerged in some studies of the Padua Inventory (Sternberger & Burns, 1990), although others (Kyrios, Bahr, & Wade, 1996) found no such differences. Finally, we wished to examine convergent and divergent validity of the OCI-R, especially of its hoarding subscale, since the validity of this subscale has been questioned (Foa et al., 2002). For this purpose, we included an additional measure of hoarding, the Saving Inventory—Revised (SI-R; Frost, Steketee, & Grisham, 2004).

2. Method 2.1. Participants The sample consisted of 381 undergraduate students (291 female, 85 male, 5 unspecified) from two different Spanish universities (University of Balearic Islands and Autonomous University of Barcelona). Ethical approval was obtained from the ethical committees of the two universities. Participation was voluntary and no payment or course credits were offered to the participants. The mean age was 21.09 years (S.D. = 2.65). 2.2. Measures 2.2.1. Obsessive–Compulsive Inventory—Revised (OCI-R) The OCI-R (Foa et al., 2002) is a 18-item self-administered questionnaire designed to assess distress associated with obsessive–compulsive symptoms. It requests a response on a 0–4 scale. The total OCI-R score is the sum of all items and it ranges from 0 to 72. The original version of the OCI-R was translated to Spanish by two of us (D.M.C. and M.A.F.) and back-translated by a professional bilingual translator. The translated version was then reviewed by the authors in order to verify the accuracy of the translation. The Spanish OCI-R is available from the first author upon request. 2.2.2. Padua Inventory (PI) The Spanish version (Mataix-Cols, Sanchez-Turet, & Vallejo, 2002) of the PI (Sanavio, 1988) is a 60-item questionnaire that assesses the degree of disturbance

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caused by intrusive thoughts and rituals. Scores range from 0 to 240. Factor analyses have yielded a four-factor structure (two obsessive and two compulsive factors), replicated across different studies in non-clinical samples (Macdonald & de Silva, 1999; Mataix-Cols et al., 2002; Sanavio, 1988; Van Oppen, 1992). These factors are named: Mental Control, Checking, Impulses, and Washing. Its Spanish version has high internal consistency, good test-retest reliability, and acceptable discriminant and convergent validity (Mataix-Cols, Sanchez-Turet, et al., 2002). 2.2.3. Saving Inventory—Revised (SI-R) The SI-R (Frost et al., 2004) is a 23-item questionnaire designed to provide a comprehensive assessment of hoarding behaviors. It requests a response on a 0–4 scale about the extent to which the symptom described in each item is present. Factor analysis has identified three factors, named difficulty discarding, excessive clutter, and excessive acquisition. Scores range from 0 to 92. The Spanish version (Tortella-Feliu et al., submitted) also has a three-factor structure, good internal consistency and test-retest reliability, and moderate divergent validity. 2.2.4. Beck Depression Inventory (BDI) The Spanish version (Sanz & Va´zquez, 1998) of the BDI (Beck & Steer, 1987) is a 21-item self-report scale of depressive symptoms. Scores range from 0 to 64. The Spanish version has demonstrated good reliability and validity estimates in both non-clinical (Sanz & Va´zquez, 1998) and clinical (Vazquez & Sanz, 1999) samples. 2.2.5. State-Trait Anxiety Inventory, trait subscale (STAI-T) The Spanish version of the STAI-T (Spielberger, Gorsuch, & Luschene, 1982) was used to assess trait anxiety. The STAI-T is a 20-item questionnaire rated on a 0–3 scale. Total scores range from 0 to 60. It is one of the most used trait anxiety scales both in clinical practice and in experimental research. It has demonstrated sound psychometric properties. 2.3. Procedure All participants were administered the questionnaires in a group setting during a lecture period. A brief description of the purpose of the study was given and written consent was obtained. Since Hajcak et al. (2004) found significant order effects for the OCI-R and the MOCI, with lower means when each measure was presented second, a subset of participants (n = 284) completed the OCI-R first, followed by the PI and the other measures. The rest of participants (n = 97) completed the PI first, followed by the OCI-R and the other measures. Sixty-four individuals completed a second administration of the OCI-R one month later and constituted the sample for test-retest reliability.


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3. Results 3.1. Factor structure of the Spanish OCI-R We conducted a confirmatory factor analysis using AMOS 5.0 in SPSS version 11.5. We evaluated the fit of our data to the original six-factor structure by Foa et al. (2002), using the maximum likelihood estimation method. To facilitate comparability, we considered the same fit indices as Foa et al. (2002) and Hajcak et al. (2004). The model had a significant x2 [x2 (129) = 331.08, P < .0001], a Goodness-of-Fit Index (GFI) of .90, a Comparative Fit Index (CFI) of .90, a rootmean-square residual (RMR) of .05, and a root-mean-square error of approximation (RMSEA) of .06. Considering criteria by Hu and Bentler (1999) (adequate fit indices are GFI and CFI of .90 or greater and RMR and RMSEA values of .06 or lower) our results, except for the chi-square, indicate a good fit for the six-factor model, with similar values to those presented by Hajcak et al. (2004). We also tested a one-factor model, and as in Hajcak et al. (2004), most indices suggested a poor fit (x2 (135) = 952.41, P < .0001; GFI = .773; CFI = .62; RMR = .09; RMSEA = .12). Standardized parameter estimates are available from the first author on request. Based on the above results, we therefore used the original subscales developed by Foa et al. (2002) in all subsequent analyses. 3.2. Correlations among OCI-R scales Cohen’s, (1988) criteria were used to evaluate the size of the correlations. Correlations >.50 will be defined as ‘‘large’’, from .30 to .49 as ‘‘medium’’, and from .10 to .29 as ‘‘small’’. Correlations between each of the subscales and the total scale of the OCI-R were large but inter-correlations among the subscales were only moderate (ranging between .27 and .47), reflecting a relatively small overlap between them (see Table 1). 3.3. Normative data, internal consistency, and gender differences Table 2 shows the means, standard deviations and Cronbach’s a coefficients for the total OCI-R and each of its subscales. For the whole sample, the mean score for the OCI-R was 15.59 (S.D. = 9.34; range = 1–55), which was slightly lower than previous studies with similar samples: 18.82 in Foa et al. (2002) study and 18.91 in Hajcak et al. (2004) study. Men tended to score higher than women but this difference did not reach statistical significance [t (367) = 1.95, P = .051]. Internal consistency for the full scale of the OCI-R was good (a = .86). Regarding the subscales, internal consistency was good for the obsessing subscale, acceptable for the checking subscale and moderate for the rest of subscales. As in previous studies of both the OCI-R (Foa et al., 2002; Hajcak et al., 2004) and the OCI (Wu & Watson, 2003), the neutralizing subscale had the lowest

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Table 1 Correlations among OCI-R subscales* Subscale

Obsessing

Hoarding

Ordering

Checking

Neutralizing

Total

Washing Obsessing Hoarding Ordering Checking Neutralizing

.34

.34 .38

.35 .27 .42

.41 .35 .40 .30

.45 .44 .43 .27 .47

.65 .71 .73 .65 .70 .69

*

All P-values