Schizotypal, Dissociative, and Imaginative Processes in a Clinical OCD Sample Stella-Marie Paradisis,1,2 Frederick Aardema,1,2 and Kevin D. Wu3 1

Research Centre, Montreal Mental Health University Institute University of Montreal 3 Department of Psychology, Northern Illinois University 2

Objective:

Previous research in a nonclinical sample has suggested that schizotypal, dissociative, and imaginative processes may play a role in obsessive-compulsive disorder (OCD) symptoms (Aardema & Wu, 2011). The present study aims to extend these findings in a clinical sample. Method: N= 75 adults (mean age = 37.99; 61.3% female), meeting the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, diagnostic criteria for OCD completed a battery of self-report questionnaires measuring schizotypal, dissociative, and imaginative processes. Results: Hierarchical regression analyses revealed inferential confusion and dissociation to be the strongest predictors of OCD symptoms, replicating and extending the findings by Aardema and Wu (2011). Conclusion: Results support the notion that inferential confusion and dissociation are important variables to consider in understanding symptoms of OCD independently from obsessive beliefs and negative mood states.  C 2015 Wiley Periodicals, Inc. J. Clin. Psychol. 00:1–19, 2015.

Keywords: schizotypy; imagination; dissociation; inferential confusion; obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a chronic, debilitating mental illness that is characterized by both obsessions (recurrent intrusive thoughts, images, or urges of an unwanted and persistent nature) and compulsions (ritualistic behaviors or mental acts that an individual feels compelled to perform to reduce anxiety; American Psychiatric Association [APA], 2013). Although there is a lack of consensus as to the exact ways in which OCD symptoms cluster together (Calamari et al., 2004), a meta-analysis (Bloch, Landeros-Weisenberger, Rosario, Pittenger, & Leckman, 2008) involving 21 studies and 5,124 people revealed symmetry, cleaning, hoarding, forbidden thoughts (e.g., aggressive, religious), and checking as common symptom dimensions. Similarly, Abramowitz and colleagues (2010) found that OCD could be divided into four symptom dimensions (unacceptable thoughts, symmetry/incompleteness, contamination, and responsibility for harm and mistakes), while exploratory and confirmatory factor analyses by Wu and Carter (2008) revealed rituals, impulses, contamination, checking, and hoarding as common symptom dimensions. Most cognitive models of OCD claim that it is not the content of intrusive thoughts that determine whether they develop into obsessions, but the way in which these thoughts are interpreted according to specific obsessive beliefs (Salkovskis, 1985). Specifically, the cognitive appraisal model of OCD holds that a “normal” cognition transitions into the realm of obsessions when it is falsely appraised as being “personally significant, revealing and threatening” (Rachman, 1997, p. 794). Various underlying beliefs relevant to OCD have been implicated in the transition from

This study was supported by a grant (no. 111261) to Frederick Aardema from the Canadian Institutes for Health Research (CIHR). Frederick Aardema is also a recipient of the CIHR New Investigator Award and a research scholar award from the Quebec Health Research Fund (Fonds de la recherche en sant´e du Qu´ebec). We thank our recruitment coordinator Karine Bergeron for her assistance with the study. Please address correspondence to: Stella-Marie Paradisis, Research Centre, Montreal Mental Health University Institute, 7331 Hochelaga, Montr´eal, Qu´ebec, H1N 3V2, Canada. E-mail: [email protected] JOURNAL OF CLINICAL PSYCHOLOGY, Vol. 00(0), 1–19 (2015) Published online in Wiley Online Library (wileyonlinelibrary.com/journal/jclp).

 C 2015 Wiley Periodicals, Inc. DOI: 10.1002/jclp.22173

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intrusions to obsessions. The Obsessive Beliefs Questionnaire-44 (OBQ-44; Obsessive Compulsive Cognitions Working Group [OCCWG], 2005) assesses several beliefs that are relevant to OCD, including intolerance of uncertainty, perfectionism, overimportance of thoughts, need for control, overestimation of threat, and inflated responsibility (OCCWG, 2001; 2003). Subsequent research with the OBQ found a strong overlap in variance among these obsessive beliefs subscales as well as inconsistent evidence that these beliefs are specific to OCD (Polman, O’Connor, & Huisman, 2011; Tolin, Woods, & Abramowitz, 2003). Despite these limitations, obsessive beliefs do appear to predict OCD symptoms independently from anxiety and depression (Abramowitz, Khandker, Nelson, Deacon, & Rygwall, 2006; OCCWG, 2005). As research continues to refine the content and measurement of belief domains, this work has the potential to further our understanding of OCD symptom development. Another line of research has highlighted inherent characteristics of the obsessions themselves that might play a role in symptom development (Aardema & Wu, 2011). In other words, rather than focusing solely on the negative consequences of appraisals of intrusive cognitions, it is also of interest as to how people with OCD come to accept the premise of the intrusive thought, especially in obsessions of a more bizarre character. For example, the peculiar nature of some obsessive thoughts (e.g., I might cause harm with my thoughts) has led some researchers to believe that schizotypal thinking may play an important role in the development of obsessions (McKay & Gruner, 2008). In addition, early clinical research into treatment-resistant OCD noted that individuals who did not benefit from traditional behavior therapy also presented with elevated levels of investment into the logic of their obsessive thoughts (Foa, Steketee, Grayson, & Doppelt, 1983; Rachman, 1983). These fixed ideas termed “overvalued ideations” do not derive their content from typical life experiences and tend to be held with a near delusional level of conviction (O’Connor, Aardema, & P´elissier, 2005; Veale, 2002). Indeed, research has demonstrated a potential connection between OCD and schizotypal symptoms (Jenike, Baer, Miniciello, Schwartz, & Carey, 1986; Tallis & Shafran, 1997). It is particularly important to assess the degree of fixity of beliefs in individuals with OCD, as individuals with poor insight into the irrationality of their symptoms typically do not respond as well to traditional cognitive-behavioral therapy (Foa, Abramowitz, Franklin, & Kozak, 1999; Neziroglu, Stevens, Yaryura-Tobias, & McKay, 2001). Sobin and colleagues (2000) found that half of the participants in a sample of individuals with clinically significant levels of OCD also demonstrated mild to severe symptoms of schizotypy. Likewise, Muris and Merckelbach (2003) found that the schizotypal symptom of fantasy proneness was significantly related to symptoms of OCD. Furthermore, Tolin, Abramowitz, Kozak, and Foa (2001) found that OCD–schizotypy relations differed by OCD subtype: Individuals with religious or harm-related obsessions (by impulse or mistake) reported greater levels of perceptual aberrations, magical ideations, and fixity of belief. A more recent study, however, did not find schizotypal symptoms to be related to any specific subtypes of OCD, after controlling for dissociation and other imaginative processes, with the exception of hoarding, which was independently predicted by schizotypy (Aardema & Wu, 2011). Related to schizotypal features, the intensity of obsessions has also been noted as a characteristic potentially operating independently from obsessive beliefs and appraisals. For the individual with OCD, obsessions may be experienced with “hallucinatory vividness,” making them almost impossible to dismiss as irrelevant occurrences (Guidano & Liotti, 1983). The strong reality value and intensity of some obsessions have led researchers to suggest a high level of imaginative absorption among individuals with OCD. An experimental study found that those with OCD are more strongly affected by possibility-based information (e.g., “I could have made a mistake” and “I might have caused someone harm”; Aardema, O’Connor, P´elissier, & Lavoie, 2009) than are nonclinical controls. Despite the fact that the doubting inference is purely a product of an individual’s own imagination (Aardema, Kleijer, Trihey, O’Connor, & Emmelkamp, 2006) and is both improbable and unrealistic in the here and now (Aardema et al., 2009; Aardema et al., 2010; O’Connor et al., 2005), the subjective narrative sustaining the doubt is accorded undue weight (O’Connor, Ecker,

Schizotypy, Dissociation, and Imagination in OCD

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Lahoud, & Roberts, 2012). In these cases, the subjective narrative overrides reality to the point that the person with OCD no longer trusts the information available through common sense and the senses. In other words, the individual’s subjective narrative serves to maintain doubt despite a lack of reality-based information, indicating that there is reason for the doubt (O’Connor et al., 2005; O’Connor et al., 2012). According to the inference-based approach (O’Connor et al., 2005) to OCD, doubting pre-existing sensory or common sense knowledge that all is correct can be differentiated from true uncertainty, whereby the individual has no prior information on which to base an evaluation of a given situation (O’Connor, 2014; O’Connor et al., 2005). It holds that the person with OCD is not so much intolerant to uncertainty as that he or she creates uncertainty where there should be none. Specifically, an obsessional reasoning process termed “inferential confusion” is characterized by an overreliance on the imagination and a distrust of the senses and has been suggested to contribute to OCD symptom development. Inferential confusion is independent from other cognitive domains, including intolerance of uncertainty and inflated responsibility (Aardema, Radomsky, O’Connor, & Julien, 2008). To assess these reasoning processes, Aardema and colleagues (Aardema, O’Connor, Emmelkamp, Marchand, & Todorov, 2005) developed the Inferential Confusion Questionnaire, which has been strongly related to symptoms of OCD, independently of other cognitive domains and negative mood states in both nonclinical and clinical samples (Aardema et al., 2005; Aardema et al., 2006; Aardema et al., 2008). For example, a small-scale clinical study demonstrated that individuals receiving inference-based therapy, which addresses inferential confusion in individuals with OCD, had equal treatment outcome as those receiving standard cognitivebehavioral therapy targeting appraisals (O’Connor et al., 2005). There was evidence for the treatment to be more effective than standard cognitive-behavioral therapy among those with a high personal investment in their obsessions. Overall, then, the construct of inferential confusion has been quite useful for understanding OCD symptom development and informing treatment, and while not incompatible with appraisal models, it focuses on a different step within the obsessional sequence centered on an overreliance on the imagination during reasoning (Clark & O’Connor, 2004). A related type of imaginative process proposed to play a role in symptoms of OCD is dissociation. Dissociative symptoms significantly relate to symptoms of OCD, especially with respect to checking compulsions (Grabe et al., 1999; Rufer, Fricke, Held, Cremer, & Hand, 2006; Watson, Wu, & Cutshall, 2004). In addition, Lochner et al. (2004) classified 15.8% of people with OCD as high dissociators. Still, most studies investigating the relationship between dissociative symptoms and OCD symptoms do not control for general distress. Further, levels of dissociation in those with OCD are not always higher than those found in anxious controls (Goff, Olin, Jenike, Baer, & Buttolph, 1992). Some have suggested that individuals with OCD become so absorbed into their obsessions due to inferential confusion that symptoms of dissociation from reality may occur (O’Connor et al., 2005). Others have emphasized an OCD-specific variant of dissociation—a self-related sense of incompleteness that contributes to an “incomplete” recol¨ lection of one’s actions, which may in turn account for compulsive behaviors (Ecker & Gonner, ¨ 2006; Ecker, Kupfer, & Gonner, 2013).

Aims and Hypotheses Previous research has suggested relations between imaginative, dissociative, and schizotypal processes and OCD symptoms. In particular, Aardema and Wu (2011) found inferential confusion and dissociation to be the most consistent predictors of OCD symptom development. However, this study was conducted using a nonclinical sample, which limits the generalizability of the findings to clinical OCD. Also, Aardema and Wu (2011) did not include a measure of obsessive beliefs, which could potentially account for the relations between schizotypal, dissociative, and imaginative processes with OCD symptoms. There are currently no studies that have investigated these constructs simultaneously to identify the most crucial variables relevant to OCD. Specifically, the relations between schizotypal, dissociative, and imaginative processes with OCD symptoms have yet to be determined in clinical populations and after controlling for other key

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factors such as negative mood states and obsessive beliefs. The main hypotheses of the current study are as follows: H1: Obsessive beliefs, schizotypy, dissociation, and inferential confusion all will relate significantly to OCD symptoms. H2: Inferential confusion and dissociation will be the strongest predictors of OCD symptoms, after controlling for negative mood states and obsessive beliefs.

Table 1 Means, Standard Deviations, Internal Consistency, and Intercorrelations

ICQ-EV SPQ DES-II OBQICT OBQPC OBQRT

M

SD

ICQ-EV

SPQ

DES-II

OBQICT

OBQPC

OBQRT

108.07 19.67 11.04 38.49 73.85 63.89

36.45 15.00 10.86 18.23 22.08 22.59

.97

.30* .96

.23* .39** .92

.43** .01 .09 .92

.34** .30* .21 .30* .93

.59** .34** .10 .56** .48** .91

Note. M – mean; SD = standard deviation; ICQ-EV = Inferential Confusion Questionnaire-Expanded Version; SPQ = Schizotypal Personality Questionnaire; DES-II = Dissociative Experiences Scale; OBQICT = Obsessive Beliefs Questionnaire-Importance/Control Subscale; OBQPC = Obsessive Beliefs QuestionnairePerfectionism/Certainty Subscale; OBQRT = Obsessive Beliefs Questionnaire-Responsibility/Threat Subscale. N = 70–75. Diagonal indicates Cronbach’s alpha. **Correlation is significant at p < .01. *Correlation is significant at p < .05.

Table 2 Descriptive Statistics for the Symptom Measures and Correlations With the Cognitive Measures

VOCI Total score Obsessions Checking Contamination Indecisiveness Hoarding Just right YBOCS Total score Obsessions Compulsions BAI BDI-II

M

SD

Alpha

ICQ-EV

SPQ

DES-II

OBQICT

OBQPC

OBQRT

68.77 9.66 11.74 12.33 10.04 6.96 18.93

31.37 9.91 8.51 11.08 5.77 8.25 11.36

.92 .90 .95 .92 .83 .95 .89

.46** .42** .46** .43** .37** -.13 .36**

.39** .21 .30* .10 .39** .33** .39**

.48** .45** .23* .24* .42** .15 .50**

.22 .45** .14 .01 .17 -.29* .08

.51** .21 .31** .16 .54** .21 .51**

.47** .37** .39** .22 .40** .00 .32**

25.67 13.00 12.67 13.17 14.68

6.90 3.71 4.18 9.81 9.52

.85 .77 .83 .88 .88

.38** .34** .32** .37** .23*

.23 .16 .23 .45** .47**

.24* .08 .32** .30** .28*

.03 .17 -.10 .17 .13

.26* .27* .19 .36** .45**

.29* .29* .22 .42** .30*

Note. M - mean; SD = standard deviation; VOCI = Vancouver Obsessional Compulsive Inventory; YBOCS = Yale-Brown Obsessive-Compulsive Scale; BAI = Beck Anxiety Inventory; BDI-II = Beck Depression Inventory; ICQ-EV = Inferential Confusion Questionnaire-Expanded Version; SPQ = Schizotypal Personality Questionnaire; DES-II = Dissociative Experiences Scale; OBQICT = Obsessive Beliefs QuestionnaireImportance/Control Subscale; OBQPC = Obsessive Beliefs Questionnaire-Perfectionism/Certainty Subscale; OBQRT = Obsessive Beliefs Questionnaire-Responsibility/Threat Subscale. N = 70–75. **Correlation is significant at p < .01. *Correlation is significant at p < .05.

Schizotypy, Dissociation, and Imagination in OCD

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Table 3a Hierarchical Regressions Predicting Overall Symptoms and Subtypes of OCD as Measured by the VOCI Total Score (Controlling for OBQ-44 Subscales) B

SE

Predicting VOCI-Total Step 1 BAI BDI-II

0.11 10.26

3.74 3.66

Step 2 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT

−3.24 8.15 −1.91 0.33 0.45

3.60 3.52 2.61 .17 .19

Step 3 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT SPQ DES-II ICQ-EV

−6.32 7.54 −3.31 0.24 0.29 0.54 18.84 0.29

3.14 3.09 2.34 0.15 0.19 1.85 6.49 0.10

Adj. R2

β

Test statistic

p value

.01 .47

F(2, 63) = 8.88 0.03 2.80

< .001 .977 .007

−.14 .37 −.09 .24 .33

F(5, 60) = 7.19 −0.90 2.31 −0.73 1.92 2.37

< .001 .371 .024 .467 .060 .021

−.28 .34 −.15 .17 .21 .03 .31 .33

F(8, 57) = 9.35 −2.01 2.44 −1.42 1.59 1.56 0.29 2.90 2.88

< .001 .049 .018 .162 .118 .125 .770 .005 .006

.20

.32

.51

Note. OCD = obsessive-compulsive disorder; SE = standard error; VOCI-Total = Vancouver Obsessional Compulsive Inventory-Total Score; BAI = Beck Anxiety Inventory; BDI-II = Beck Depression Inventory; OBQ = Obsessive Beliefs Questionnaire; OBQ-ICT = OBQ-Importance/Control Subscale; OBQ-PC = OBQ-Perfectionism/Certainty Subscale; OBQ-RT = OBQ-Responsibility/Threat Subscale; SPQ = Schizotypal Personality Questionnaire; DES-II = Dissociative Experiences Scale; ICQ-EV = Inferential Confusion Questionnaire-Expanded Version.

Method Participants Participants were 75 adults meeting the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR; APA, 2000) diagnostic criteria for OCD. Participants were recruited through existing research programs at the Centre de recherche de l’Institut universitaire en sant´e mentale de Montr´eal. Eligibility was determined using a two-stage assessment process as follows: (a) a standard telephone screening interview based on DSM-IV-TR criteria for OCD, as well as several other disorders studied at the center (e.g., tic disorder, body dysmorphic disorder); and (b) a face-to-face diagnostic interview by a trained evaluator who was independent to the study. The diagnostic interview included three semistructured interviews. First, all participants were administered the Structured Clinical Interview for DSM-IV Axis I Disorders, Research Version, Patient Edition (SCID-I/P; First, Spitzer, Gibbon, & Williams, 2002). The SCID-I has “superior validity” (Grabill, Merlo, Duke, Harford, & Storch, 2008) as a diagnostic tool, according to established standards (Basco et al., 2000), and has good test-retest reliability (k = .35 to 1.0; Grabill et al., 2008). Second, participants were administered the YaleBrown Obsessive-Compulsive Scale (YBOCS; cut-off score ࣙ 16; Goodman, Price, Rasmussen, & Mazure, 1989a,1989b). Third, the SCID for DSM-IV Axis II Personality Disorders (SCID-II; First, Gibbon, Spitzer, Williams, & Benjamin, 1997; see Maffei et al., 1997, for reliability) was administered as an assessment of personality dimensions that may have an effect on treatment engagement, compliance, or outcome (e.g., Dreessen, Hoekstra, & Arntz, 1997; Fals-Stewart & Lucente, 1993).

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Journal of Clinical Psychology, xxxx 2015

Table 3b Hierarchical Regressions Predicting Overall Symptoms and Subtypes of OCD as Measured by the VOCI Obsessions Subscale Score (Controlling for OBQ-44 Subscales) B

SE

0.04 0.11

0.06 0.06

Step 2 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT

0.02 0.12 0.13 −0.00 0.00

0.06 0.06 0.04 0.00 0.00

Step 3 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT SPQ DES-II ICQ-EV

−0.02 0.12 0.11 −0.00 0.00 −0.02 0.31 0.00

0.06 0.06 0.04 0.00 0.00 0.03 0.11 0.00

Predicting VOCI-Obsessions Step 1 BAI BDI-II

Adj. R2

β

Test statistic

p value

.12 .32

F(2, 63) = 6.51 0.69 1.86

.003 .492 .068

.05 .34 .37 −.13 .11

F(5, 60) = 6.12 0.28 2.06 3.01 −1.02 0.81

< .001 .777 .044 .004 .310 .423

−.06 .33 .31 −.19 .10 −.08 .33 .19

F(8, 57) = 6.10 −0.41 2.12 2.55 −1.59 0.61 −0.64 2.76 1.50

< .001 .683 .038 .014 .118 .541 .523 .008 .139

.15

.28

.39

Note. OCD = obsessive-compulsive disorder; SE = standard error; VOCI-Obsessions = Vancouver Obsessional Compulsive Inventory-Obsessions Subscale; BAI = Beck Anxiety Inventory; BDI-II = Beck Depression Inventory; OBQ = Obsessive Beliefs Questionnaire; OBQ-ICT = OBQ-Importance/Control Subscale; OBQ-PC = OBQ-Perfectionism/Certainty Subscale; OBQ-RT = OBQ-Responsibility/Threat Subscale; SPQ = Schizotypal Personality Questionnaire; DES-II = Dissociative Experiences Scale; ICQEV = Inferential Confusion Questionnaire-Expanded Version.

Entry criteria for the study are as follows: (a) a primary diagnosis of OCD; (b) no change in medication type or dose during the 12 weeks before treatment for antidepressants (4 weeks for anxiolytics); (c) willingness to keep medication stable while participating in the study; (d) no evidence of suicidal intent; (e) no evidence of current substance abuse; and (f) no evidence of current or past schizophrenia, bipolar, or organic mental disorder. After the assessment, participants completed a battery of questionnaires. For their participation, eligible participants received 24 weeks of inference-based therapy for OCD (4 weeks of evaluation and 20 weeks of treatment) free of charge. The sample comprised 61.3% women and had a mean age of 38.0 years (standard deviation [SD] = 12.8; range from 17 to 66 years).

Questionnaires The YBOCS (Goodman et al., 1989a,b) is a clinician-administered semistructured interview that is considered to be the “gold standard” assessment for OCD symptom severity (Frost, Steketee, Krause, & Trepanier, 1995). The YBOCS produces three severity scores: obsessions (five items), compulsions (five items), and total score (10 items). Responses were rated on a 5-point scale ranging from 0 (not at all) to 4 (extreme), Grabill et al. (2008) reported that this test is sensitive to treatment change and has adequate internal consistency (α = .69–.91). The Vancouver Obsessional Compulsive Inventory (VOCI; Thordarson et al., 2004) is a 55item self-report questionnaire that assesses OCD symptom severity. This questionnaire was selected due to its distinct advantage of measuring both cognitive and behavioral dimensions of OCD (Grabill et al., 2008). Symptom severity is scored on six subscales: obsessions, indecisiveness, just right, contamination, hoarding, and checking, using a 5-point scale ranging

Schizotypy, Dissociation, and Imagination in OCD

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Table 3c Hierarchical Regressions Predicting Overall Symptoms and Subtypes of OCD as Measured by the VOCI Checking Subscale Score (Controlling for OBQ-44 Subscales) B

SE

0.13 1.38

1.14 1.11

Step 2 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT

−0.81 1.09 −0.76 0.05 0.14

1.15 1.12 0.83 0.06 0.06

Step 3 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT SPQ DES-II ICQ-EV

−1.35 1.04 −1.07 0.03 0.07 0.37 1.32 0.10

1.10 1.08 0.82 0.05 0.07 0.65 2.27 0.04

Predicting VOCI-Checking Step 1 BAI BDI-II

Adj. R2

β

Test statistic

p value

.02 .23

F(2, 63) = 1.95 0.11 1.24

.151 .911 .221

−.13 .18 −.13 .12 .37

F(5, 60) = 2.60 −0.71 0.97 −0.91 0.84 2.36

.034 .479 .334 .365 .406 .022

−.22 .17 −.18 .08 .18 .08 .08 .40

F(8, 57) = 3.18 −1.24 0.96 −1.31 0.61 1.08 0.58 0.58 2.76

.005 .222 .339 .196 .546 .287 .567 .562 .008

.03

.11

.21

Note. OCD = obsessive-compulsive disorder; SE = standard error; VOCI-Checking = Vancouver Obsessional Compulsive Inventory-Checking Subscale; BAI = Beck Anxiety Inventory; BDI-II = Beck Depression Inventory; OBQ = Obsessive Beliefs Questionnaire; OBQ-ICT = OBQ-Importance/Control Subscale; OBQ-PC = OBQ-Perfectionism/Certainty Subscale; OBQ-RT = OBQ-Responsibility/Threat Subscale; SPQ = Schizotypal Personality Questionnaire; DES-II = Dissociative Experiences Scale; ICQ-EV = Inferential Confusion Questionnaire-Expanded Version.

from 0 (not at all) to 4 (very much). The VOCI has demonstrated good psychometric properties, including strong internal consistency (α = .94 total; α = .88–.96 for the subscales; Grabill et al., 2008; Thordarson et al., 2004). The OBQ-44 (OCCWG, 2005) is a 44-item self-report measure that assesses belief domains in clinical and nonclinical populations. The level of agreement with each statement is rated on a 7-point scale ranging from 1 (disagree very much) to 7 (agree very much). The OBQ-44 comprises three underlying factors: responsibility/threat estimation (RT), perfectionism/certainty (PC), and importance/control of thoughts (ICT; OCCWG, 2005). Internal consistency generally is strong (αs range from .90–.93; Tolin, Worhunsky, & Maltby, 2006). The Dissociative Experiences Scale (DES-II; Carlson & Putnam, 1993) is a 28-item self-report measure that assesses the frequency of dissociation in clinical and nonclinical populations. Responses are rated on an 11-point scale (0 to 100, increasing by increments of 10). The overall score is obtained by adding up the 28 item scores and dividing by 28: This yields an overall score ranging from 0 to 100. The DES-II comprises three underlying factors: amnesic dissociation, absorption/imaginative involvement, and depersonalization/derealization (Carlson et al., 1991). Reliability varies between α = .93 (Van IJzendoorn & Schuengel, 1996) and .95 (Frischholz et al., 1990). Inferential Confusion Questionnaire-Expanded Version (ICQ-EV; Aardema et al., 2010) is a 30-item self-report questionnaire that measures the propensity of individuals with OCD to distrust their senses and confound the imaginary nature of their obsessions with reality due to faulty reasoning processes. Responses are rated on a 6-point scale ranging from 1 (strongly disagree) to 6 (strongly agree), with elevated scores indicating a distrust of the senses and

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Table 3d Hierarchical Regressions Predicting Overall Symptoms and Subtypes of OCD as Measured by the VOCI Contamination Subscale Score (Controlling for OBQ-44 Subscales) B

SE

Predicting VOCI-Contamination Step 1 BAI BDI-II

0.12 −0.06

0.25 0.25

Step 2 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT

−0.02 −0.09 −0.24 0.01 0.02

0.26 0.26 0.19 0.01 0.01

Step 3 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT SPQ DES-II ICQ-EV

−0.18 −0.06 −0.38 0.00 0.01 −0.07 0.73 0.03

0.24 0.24 0.18 0.01 0.01 0.14 0.50 0.01

Adj. R2

β

Test statistic

p value

.09 −.05

F(2, 63) = .12 0.46 −0.24

.891 .649 .811

−.02 −.07 −.19 .08 .28

F(5, 60) = .84 −0.08 −0.36 −1.26 0.52 1.63

.527 .939 .724 .212 .607 .108

−.14 −.04 −.30 .02 .10 −.07 .20 .51

F(8, 57) = 2.93 −0.76 −0.23 −2.15 0.17 0.55 −0.49 1.47 3.47

.008 .448 .816 .036 .867 .582 .629 .148 .001

−.03

−.01

.19

Note. OCD = obsessive-compulsive disorder; SE = standard error; VOCI-Contamination = Vancouver Obsessional Compulsive Inventory-Contamination Subscale; BAI = Beck Anxiety Inventory; BDI-II = Beck Depression Inventory; OBQ = Obsessive Beliefs Questionnaire; OBQ-ICT = OBQ-Importance/Control Subscale; OBQ-PC = OBQ-Perfectionism/Certainty Subscale; OBQ-RT = OBQ-Responsibility/Threat Subscale; SPQ = Schizotypal Personality Questionnaire; DES-II = Dissociative Experiences Scale; ICQEV = Inferential Confusion Questionnaire-Expanded Version.

overreliance on the imagination. Internal consistency varies between α = .96 in nonclinical samples and .97 in clinical samples (Aardema et al., 2010). Schizotypal Personality Questionnaire (SPQ; Raine, 1991) is a self-report questionnaire based on the DSM, Third Edition, Revised (DSM-III-R; APA, 1987) criteria. The SPQ assesses each of the nine features of schizotypal personality disorder that correspond to three broad symptom categories: positive or cognitive perceptual symptoms (e.g., distorted perception); negative or interpersonal symptoms (e.g., lack of friends); and disorganized symptoms (e.g., bizarre speech patterns). This questionnaire has been previously used in OCD-relevant research (Moritz et al., 2004) and has good internal consistency (α = .91; Raine, 1991). Beck Depression Inventory-II (BDI-II; Beck, Steer, & Brown, 1996) is a 21-item self-report questionnaire that assesses symptoms of major depression. Each item is rated on a severity scale ranging from 0 to 3 for a maximum score of 63. The BDI has good internal consistency (α = .91; Dozois, Dobson, & Ahnberg, 1998). Beck Anxiety Inventory (BAI; Beck, Epstein, Brown, & Steer, 1996) is a 21-item self-report questionnaire that assesses symptoms of anxiety. Each item is rated on a severity scale ranging from 0 to 3 for a maximum score of 63. The BAI has good internal consistency (α = .92; Beck et al., 1988).

Results Data were analysed using IBM SPSS (version 16). Before correlational analyses, all questionnaire scores were checked for normality. Logarithmic transformations were performed for the DES-II

Schizotypy, Dissociation, and Imagination in OCD

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Table 3e Hierarchical Regressions Predicting Overall Symptoms and Subtypes of OCD as Measured by the VOCI Indecisiveness Score (Controlling for OBQ-44 Subscales) B

SE

Predicting VOCI-Indecisiveness Step 1 BAI BDI-II

−0.57 2.35

0.71 0.70

Step 2 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT

−1.20 1.81 −0.40 0.09 0.08

0.67 0.65 0.48 0.03 0.04

Step 3 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT SPQ DES-II ICQ-EV

−1.61 1.65 −0.52 0.08 0.06 0.23 2.57 0.03

0.64 0.63 0.48 0.03 0.04 0.38 1.33 0.02

Adj. R2

β

Test statistic

p value

−.13 .56

F(2, 63) = 8.89 −0.80 3.36

< .001 .430 .001

−.28 .43 −.10 .33 .30

F(5, 60) = 8.41 −1.80 2.77 −0.83 2.72 2.26

< .001 .077 .007 .409 .009 .028

−.38 .39 −.12 .28 .23 .07 .22 .19

F(8, 57) = 7.21 −2.51 2.61 −1.08 2.43 1.56 0.61 1.93 1.52

< .001 .015 .012 .286 .018 .124 .543 .058 .135

.20

.36

.43

Note. OCD = obsessive-compulsive disorder; SE = standard error; VOCI-Indecisiveness = Vancouver Obsessional Compulsive Inventory-Indecisiveness Subscale; BAI = Beck Anxiety Inventory; BDI-II = Beck Depression Inventory; OBQ = Obsessive Beliefs Questionnaire; OBQ-ICT = OBQ-Importance/Control Subscale; OBQ-PC = OBQ-Perfectionism/Certainty Subscale; OBQ-RT = OBQ-Responsibility/Threat Subscale; SPQ = Schizotypal Personality Questionnaire; DES-II = Dissociative Experiences Scale; ICQEV = Inferential Confusion Questionnaire-Expanded Version.

as well as the VOCI Obsessions and Hoarding subscales, while square root transformations were performed on the VOCI Contamination subscale, the OBQ ICT subscale, the BAI, the BDI, and the SPQ. Analyses involving the subscales of the DES-II and SPQ were not included due to excessive skewness after transformations.

Means, Standard Deviations, and Intercorrelations Means, standard deviations, and intercorrelations among the cognitive measures are reported in Table 1. All of the scales showed internal consistency values between .91 and .97. In general, measures demonstrated low to moderate intercorrelations as well as an adequate level of discriminant validity.

Schizotypy, Dissociation, Cognitive Domains, and OCD Symptoms The relations among relevant variables, negative mood states, and OCD symptoms are reported in Table 2. Coefficient alpha values ranged from .77 to .95. Overall, the ICQ-EV, the SPQ, and the DES-II demonstrated significant correlations with the VOCI total and subscales, with the exception of hoarding for the ICQ-EV and DES-II and contamination and obsessions for the SPQ. Similar results were demonstrated with the YBOCS, with the exception of the SPQ and obsessions for the DES-II. All measures also demonstrated significant relations with the BAI and the BDI; the SPQ demonstrated a stronger relationship to these negative mood states than to OCD symptoms.

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Table 3f Hierarchical Regressions Predicting Overall Symptoms and Subtypes of OCD as Measured by the VOCI Hoarding Subscale Score (Controlling for OBQ-44 Subscales) B

SE

Predicting VOCI-Hoarding Step 1 BAI BDI-II

−0.17 0.24

0.07 0.06

Step 2 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT

−0.19 0.23 −0.17 0.00 0.00

0.06 0.06 0.05 0.00 0.00

Step 3 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT SPQ DES-II ICQ-EV

−0.20 0.20 −0.14 0.00 0.00 0.08 0.05 −0.00

0.06 0.06 0.05 0.00 0.00 0.04 0.13 0.00

Adj. R2

β

Test statistic

p value

−.45 .65

F (2, 63) = 7.44 −2.68 3.85

.001 .009 < .001

−.50 .62 −.45 .16 .18

F (5, 60) = 6.38 −3.03 3.80 −3.66 1.22 1.24

< .001 .004 < .001 .001 .226 .218

−.53 .53 −.38 .14 .13 .28 .04 −.08

F (8, 57) = 4.96 −3.23 3.21 −3.00 1.11 0.84 2.21 0.35 −0.58

< .001 .002 .002 .004 .271 .403 .031 .728 .561

.17

.29

.33

Note. OCD = obsessive-compulsive disorder; SE = standard error; VOCI-Hoarding = Vancouver Obsessional Compulsive Inventory-Hoarding Subscale; BAI = Beck Anxiety Inventory; BDI-II = Beck Depression Inventory; OBQ = Obsessive Beliefs Questionnaire; OBQ-ICT = OBQ-Importance/Control Subscale; OBQ-PC = OBQ-Perfectionism/Certainty Subscale; OBQ-RT = OBQ-Responsibility/Threat Subscale; SPQ = Schizotypal Personality Questionnaire; DES-II = Dissociative Experiences Scale; ICQ-EV = Inferential Confusion Questionnaire-Expanded Version.

Predicting OCD Symptoms and Subtypes To assess the relative contribution of each variable in the prediction of OCD symptoms, we performed hierarchical regressions to predict scores on both the VOCI (Tables 3a–g) and the YBOCS (Tables 4a–c) while controlling for the OBQ subscales, the BAI, and the BDI scores. The first regression predicted the VOCI total score. In step 1, we entered the BAI and the BDI. Collectively, they explained approximately 20% of the variance in overall OCD symptoms, R2 = .20; F(2, 63) = 8.88, p < .001, with the BDI as the only significant predictor. In step 2, we entered the three OBQ subscales; together, they significantly augmented the portion of explained variance to 32%, R2 = .32; F(5, 60) = 7.19, p < .001. In this case, the association between factors is due to the BDI and the OBQRT. The OBQPC subscale approached significance (p = .06). Finally, in step 3, we entered the ICQ-EV, the SPQ, and the DES-II, and their addition increased the amount of explained variance for this model to 51%, R2 = .51; F(8, 57) = 9.35, p < .001. The most significant predictors at this step were the DES-II and the ICQ-EV, followed by the BAI and the BDI. Neither the OBQ subscales nor the SPQ emerged as a significant predictor in this step. The six remaining hierarchical regressions were conducted in the same fashion to determine whether there were differences in how each variable related to specific OCD symptom dimensions (see Tables 3b–g). Results indicated unique patterns of predictors for each OCD symptom dimension. Specifically, for the obsessions subscale, the strongest predictor was the DES-II, followed by the OPQICT and the BDI-II. For checking, the only significant predictor was the ICQ-EV. For contamination, the strongest predictors were the ICQ-EV and the OBQICT. For indecisiveness, the most significant predictors were the BAI and the BDI-II, followed by the

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Table 3g Hierarchical Regressions Predicting Overall Symptoms and Subtypes of OCD as Measured by the VOCI Just Right Subscale Score (Controlling for OBQ-44 Subscales) B

SE

0.29 3.35

1.39 1.37

Step 2 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT

−0.43 2.23 −1.35 0.19 0.08

1.35 1.32 0.98 0.07 0.07

Step 3 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT SPQ DES-II ICQ-EV

−1.54 1.94 −1.78 0.16 0.03 0.33 6.93 0.10

1.20 1.19 0.90 0.06 0.07 0.71 2.49 0.04

Predicting VOCI-Just Right Step 1 BAI BDI-II

Adj. R2

β

Test statistic

p value

.04 .42

F (2, 63) = 7.64 0.21 2.46

.001 .834 .017

−.05 .28 −.17 .38 .16

F (5, 60) = 8.25 −0.32 1.69 −1.37 2.94 1.14

< .001 .752 .097 .176 .005 .260

−.19 .24 −.22 .31 .05 .05 .31 .30

F (8, 57) = 7.89 −1.28 1.64 −1.98 2.73 0.36 0.47 2.78 2.48

< .001 .206 .108 .052 .008 .720 .640 .007 .016

.17

.29

.46

Note. OCD = obsessive-compulsive disorder; SE = standard error; VOCI-Just Right = Vancouver Obsessional Compulsive Inventory-Just Right Subscale; BAI = Beck Anxiety Inventory; BDI-II = Beck Depression Inventory; OBQ = Obsessive Beliefs Questionnaire; OBQ-ICT = OBQ-Importance/Control Subscale; OBQ-PC = OBQ-Perfectionism/Certainty Subscale; OBQ-RT = OBQ-Responsibility/Threat Subscale; SPQ = Schizotypal Personality Questionnaire; DES-II = Dissociative Experiences Scale; ICQEV = Inferential Confusion Questionnaire-Expanded Version.

OBQPC, with the DES-II approaching significance (p = .058). For hoarding, the most significant predictors were the BAI and BDI-II, followed by the OBQICT and the SPQ. Finally, for the “just right” subscale, the most significant predictors were the DES-II and the OBQPC, followed by the ICQ-EV; the OBQICT approached significance (p = .052). A second set of regressions was conducted to predict YBOCS scores (see Tables 4a–c). As with the previous regressions, the BAI and the BDI-II were entered in step 1, followed by the three OBQ subscales in step 2, and finally the ICQ-EV, the SPQ, and the DES-II in step 3. For the YBOCS total score, the strongest predictor was the ICQ-EV; the OBQICT approached significance (p = .054). For the YBOCS obsessions scale, none of the models from the analyses yielded statistically significant results, rendering the coefficients uninterpretable. However, results of the YBOCS compulsions scale revealed the OCQICT, the DES-II, and the ICQ-EV to be significant predictors. Hence, despite the lack of detailed information regarding specific symptom subtypes, the hierarchical regressions with the YBOCS demonstrated the relevance of the inferential confusion and dissociation to OCD symptoms.

Discussion The current study aimed to investigate how schizotypal, dissociative, and imaginative processes were relevant to predicting OCD symptoms. Previous research has found these processes to be related to OCD symptoms, but few studies controlled for negative mood states and the overlap between measures. Further, many previous studies targeted nonclinical samples. In contrast,

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Table 4a Hierarchical Regressions Predicting Overall Symptoms and Subscales of OCD as Measured by the YBOCS Total Score (controlling for OBQ-44 subscales) B

SE

Predicting YBOCS-Total Step 1 BAI BDI-II

1.59 −0.39

0.91 0.89

Step 2 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT

1.13 −0.73 −1.07 0.06 0.07

0.93 0.92 0.68 0.05 0.05

Step 3 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT SPQ DES-II ICQ-EV

0.75 −0.69 −1.35 0.05 0.03 −0.01 1.61 0.06

0.92 0.91 0.69 0.04 0.05 0.54 1.60 0.03

Adj. R2

β

Test statistic

p value

.32 −.08

F (2, 64) = 2.37 1.75 −0.44

.102 .086 .662

.22 −.15 −.22 .20 .23

F (5, 61) = 2.20 1.21 −0.79 −1.57 1.37 1.43

.065 .232 .431 .122 .176 .158

.15 −.14 −.28 .17 .10 −.00 .13 .32

F (8, 58) = 2.33 0.81 −0.76 −1.97 1.16 0.59 −0.01 1.01 2.19

.030 .420 .452 .054 .252 .560 .990 .317 .032

.04

.08

.14

Note. OCD = obsessive-compulsive disorder; SE = standard error; YBOCS-Total = Yale-Brown ObsessiveCompulsive Scale-Total Score; BAI = Beck Anxiety Inventory; BDI-II = Beck Depression Inventory; OBQ-ICT = Obsessive Beliefs Questionnaire-Importance/Control Subscale; OBQ-PC = OBQPerfectionism/Certainty Subscale; OBQ-RT = OBQ-Responsibility/Threat Subscale; SPQ = Schizotypal Personality Questionnaire; DES-II = Dissociative Experiences Scale; ICQ-EV = Inferential Confusion Questionnaire-Expanded Version.

the current study allowed for the identification of the unique contributions of schiztotypal, dissociative, and imaginative processes within a clinical sample, after controlling for negative mood states and multiple obsessive belief domains. Results showed that imaginative, dissociative, and schizotypal processes were significantly correlated with each other confirming previous findings. These processes were also significantly associated with obsessive beliefs; the exception was dissociation, which did not correlate significantly with any obsessive belief subscale. Inferential confusion and dissociative experiences were most strongly related to OCD symptoms, replicating previous findings from a nonclinical sample (Aardema & Wu, 2011). These measures, however, also related significantly to negative mood states and other obsessive belief domains, suggesting that their relations with OCD symptoms could be explained in part by a general overlap in variance with these factors. To further investigate the unique contributions of schizotypal, dissociative, and imaginative processes to OCD after controlling for negative mood states and obsessive beliefs, two sets of hierarchical regressions were performed. Consistent with hypotheses, the strongest predictors for overall OCD symptoms were inferential confusion and dissociative experiences, when predicting either the VOCI or the Y-BOCS. These findings are consistent with the notion that individuals with OCD may become so absorbed into their obsessions that a certain degree of detachment and derealization from reality may occur (O’Connor & Aardema, 2003). In terms of specific OCD symptoms, different patterns of predictors emerged. For example, inferential confusion explained a significant amount of the variance for checking, contamination, and “just right” experiences. In these cases, individuals with OCD may become so involved in their imagination and subjective narratives that they come to distrust reality-based information

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Table 4b Hierarchical Regressions Predicting Overall Symptoms and Subscales of OCD as Measured by the YBOCS Obsessions Subscale Score (Controlling for OBQ-44 subscales) B

SE

Predicting YBOCS-Obsessions Step 1 BAI BDI-II

0.86 −0.03

0.48 0.47

Step 2 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT

0.72 −0.10 −0.01 0.03 0.01

0.51 0.50 0.37 0.03 0.03

Step 3 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT SPQ DES-II ICQ-EV

0.66 −0.14 −0.10 0.03 −0.01 0.01 −0.47 0.03

0.52 0.51 0.39 0.03 0.03 0.31 0.90 0.02

Adj. R2

β

Test statistic

p value

.32 −.01

F(2, 64) = 3.42 1.78 −0.05

.039 .080 .957

.27 −.07 −.00 .16 .08

F(5, 61) = 1.82 1.42 −0.40 −0.02 1.09 0.51

.122 .162 .694 .982 .282 .611

.24 −.05 −.04 .16 −.03 .00 −.07 .25

F(8, 58) = 1.46 1.27 −0.28 −0.26 1.04 −0.18 0.03 −0.52 1.59

.192 .209 .782 .799 .302 .858 .977 .607 .116

.07

.06

.05

Note. OCD = obsessive-compulsive disorder; SE = standard error; YBOCS- Obsessions = Yale-Brown Obsessive-Compulsive Scale-Obsessions Subscale; BAI = Beck Anxiety Inventory; BDI-II = Beck Depression Inventory; OBQ-ICT = Obsessive Beliefs Questionnaire-Importance/Control Subscale; OBQ-PC = OBQ-Perfectionism/Certainty Subscale; OBQ-RT = OBQ-Responsibility/Threat Subscale; SPQ = Schizotypal Personality Questionnaire; DES-II = Dissociative Experiences Scale; ICQ-EV = Inferential Confusion Questionnaire-Expanded Version.

provided by their senses or common sense (O’Connor et al., 2005). This would lead them to continue performing their rituals because they are unable to process information indicating that all is well and that no action needs to be taken. For “just right” experiences in particular, the person with OCD may be driven to rectify an inner discomfort or self-related feeling of incompleteness (Ecker et al., 2013) by performing actions in the real world (Coles, Frost, Heimberg, & Rh´eaume, 2003; Coles, Heimberg, Frost, & Steketee, 2005). Dissociation, on the other hand, was a strong predictor for obsessions, indecisiveness, and “just right” experiences as measured by the VOCI. In addition, dissociation was a significant predictor of compulsions as measured by the Y-BOCS. As noted, experiences of dissociation are often related to imaginative absorption because becoming overly involved in one’s obsessions can lead to depersonalization and derealisation from real-life experiences. In the case of ¨ “just right” experiences, Ecker and colleagues (Ecker & Gonner, 2006; Ecker et al., 2013) have suggested that individuals with OCD may experience feelings of self-related incompleteness or depersonalisation with regard to their actions, leading to repetition of compulsive behaviors. Still, the current design does not provide direct evidence for causal explanations on the role of dissociation in OCD. Whereas results are consistent with the idea that dissociation could give rise to or exacerbate OCD symptoms, it is also possible that dissociation is a mere consequence of having OCD, in which, for example, severity of symptoms gives rise to elevated levels of dissociation. The specificity of dissociation to particular subtypes of OCD appears to suggest that the relationship is due to more than symptom severity alone, but future research may wish to focus on clarifying the causal pathways in which dissociation relates to symptoms of OCD.

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Table 4c Hierarchical Regressions Predicting Overall Symptoms and Subscales of OCD as Measured by the YBOCS Compulsions Subscale Score (Controlling for OBQ-44 subscales) B

SE

Predicting YBOCS-Compulsions Step 1 BAI BDI-II

0.73 −0.37

0.57 0.56

Step 2 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT

0.41 −0.53 −1.06 0.04 0.06

0.57 0.56 0.42 0.03 0.03

Step 3 BAI BDI-II OBQ-ICT OBQ-PC OBQ-RT SPQ DES-II ICQ-EV

0.09 −0.55 −1.26 0.03 0.04 −0.02 2.08 0.04

0.54 0.54 0.41 0.03 0.03 0.32 0.94 0.02

Adj. R2

β

Test statistic

p value

.24 −.12

F(2, 64) = .92 1.28 −0.65

.404 .206 .515

.13 −.17 −.35 .18 .30

F(5, 61) = 2.31 0.71 −0.94 −2.55 1.27 1.88

.055 .481 .349 .013 .210 .065

.03 −.18 −.42 .13 .19 −.01 .27 .31

F(8, 58) = 3.20 0.16 −1.02 −3.10 0.97 1.17 −0.05 2.21 2.20

.005 .872 .311 .003 .337 .247 .961 .031 .032

-.00

.09

.21

Note. OCD = obsessive-compulsive disorder; SE = standard error; YBOCS- Obsessions = Yale-Brown Obsessive-Compulsive Scale-Compulsions Subscale; BAI = Beck Anxiety Inventory; BDI-II = Beck Depression Inventory; OBQ-ICT = Obsessive Beliefs Questionnaire-Importance/Control Subscale; OBQPC = OBQ-Perfectionism/Certainty Subscale; OBQ-RT = OBQ-Responsibility/Threat Subscale; SPQ = Schizotypal Personality Questionnaire; DES-II = Dissociative Experiences Scale; ICQ-EV = Inferential Confusion Questionnaire-Expanded Version.

Finally, schizotypy only contributed unique variance to hoarding. These results are inconsistent with previous findings reporting that schizotypy was specifically relevant to obsessions (Tolin et al., 2001). These results are consistent with previous findings by Aardema and Wu (2011) as well as Frost and colleagues (Frost, Steketee, Williams, & Warren, 2000), who found that individuals with hoarding and nonhoarding OCD differed on schizotypal traits, and Fromm’s (1947) observation that those with a “hoarding orientation” were more likely to be inhibited and distant, displaying greater social anxiety and schizotypal traits (Frost et al., 2000; Samuels et al., 2002; Steketee & Frost, 2003; Steketee, Frost, Wincze, Greene, & Douglas, 2000). It is interesting to note that obsessive beliefs regarding importance/control of thoughts emerged as a significant predictor for obsessions, contamination, hoarding, and “just right” experiences. It makes theoretical sense and is consistent with empirical evidence that importance/control of thoughts would relate to obsessive thoughts. According to the appraisal model (OCCWG, 1997), intrusive thoughts that are considered to be distressing by an individual with OCD are often assigned abnormally high levels of importance, leading them to attempt to control or rid themselves of these thoughts through various compulsive rituals (Aardema, et al., 2013; Moulding, Aardema, & O’Connor, 2014). The fact that importance/control of thoughts emerged as a significant negative predictor for both hoarding and “just right” experiences also makes theoretical sense, as these individuals tend to have poor insight and may therefore not feel the need to suppress, censure, or dispel their obsessive thoughts (Coles et al., 2005; Ecker et al., 2013; Freeston & Ladouceur, 1997; OCCWG, 2005).

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Limitations This study has several limitations that require consideration. First, the sample size was adequate but modest, and replication in a larger clinical sample is warranted. Second, this study used three specific measures of schizotypal, dissociative, and imaginative processes. By including different measures of these processes, we may potentially expand the explanatory power of cognitive domains in OCD. Finally, although these results provide us with a more comprehensive understanding of the roles of schizotypal, dissociative, and imaginative processes in OCD, future investigations should examine how these processes relate to treatment outcome. By continuing to investigate the relations between these factors and OCD, future research will further improve our conceptualization and understanding of OCD, as well as improve treatment outcome.

Conclusion Overall, inferential confusion and dissociation significantly contributed to the prediction of OCD symptoms in this clinical sample, beyond the variance explained by other cognitive domains and negative mood states. These results lend further support to an inference-based conceptualization of OCD (Aardema et al., 2008; O’Connor et al., 1997). By examining the relative contributions of each factor in an OCD sample and in combination with other relevant cognitive belief domains, these results replicate and extend findings by Aardema and Wu (2011) while addressing several of that study’s limitations.

References Aardema, F., Kleijer, T. M. R., Trihey, M., O’Connor, K., & Emmelkamp, P. (2006). Processes of inference, schizotypal thinking and obsessive-compulsive behaviour in a normal sample. Psychological Reports, 99, 213–220. doi:10.2466/PR0.99.1.213–220 Aardema, F., Moulding, R., Radomsky, A. S., Doron, G., Allamby, J., & Souki, E. (2013). Fear of self and obsessionality: Development and validation of the Fear of Self Questionnaire. Journal of ObsessiveCompulsive and Related Disorders, 2(3), 306–315. doi:10.1016/j.jocrd.2013.05.005 Aardema, F., O’Connor, K. P., Emmelkamp, P. M. G., Marchand, A., & Todorov, C. (2005). Inferential confusion in obsessive-compulsive disorder: The inferential confusion questionnaire. Behaviour Research and Therapy, 43, 293–308. doi:10.1016/j.brat.2004.02.003 Aardema, F., O’Connor, K. P., P´elissier, M.-C., & Lavoie. (2009). The quantification of doubt in obsessivecompulsive. International Journal of Cognitive Therapy, 2, 188–205. doi:10.1521/ijct.2009.2.2.188 Aardema, F., Radomsky, A. S., O’Connor, K. P., & Julien, D. (2008). Inferential confusion, obsessive beliefs and obsessive-compulsive symptoms: A multidimensional investigation of independent cognitive domains. Clinical Psychology & Psychotherapy, 15, 227–238. doi:10.1002/cpp.581 Aardema, F., & Wu, K. D. (2011). Imaginative, dissociative and schizotypal processes in obsessivecompulsive symptoms. Journal of Clinical Psychology, 67, 74–81. doi:10.1002/jclp.20729 Aardema, F., Wu, K. D., Careau, Y., O’Connor, K., Julien, D., & Dennie, S. (2010). The expanded Version of the Inferential Confusion Questionnaire: Further development and validation in clinical and non-clinical samples. Journal of Psychopathology & Behavioural Assessment, 32(3), 448–462. doi:10.1007/s10862009-9157-x Abramowitz, J. S., Deacon, B. J., Olatunji, B. O., Wheaton, M. G., Berman, N. C., Losardo, D., . . . Hale, L. R. (2010). Assessment of obsessive-compulsive symptom dimensions: Development and evaluation of the Dimensional Obsessive-Compulsive Scale. Psychological Assessment, 22(1), 180–198. doi:10.1037/a0018260 Abramowitz, J. S., Khandker, M., Nelson, C. A., Deacon, B. J., & Rygwall, R. (2006). The role of cognitive factors in the pathogenesis of obsessive-compulsive symptoms: A prospective study. Behaviour Research and Therapy, 44, 1361–1374. doi:10.1016/j.brat.2005.09.011 American Psychiatric Association. (1987). Diagnostic and statistical manual of mental disorders (3rd ed., rev.). Washington, DC: Author. American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text rev.). Washington, DC: Author.

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