(PS7-C62) Comparison of Inference-based and Cognitive-behavioral Models of Obsessive-compulsive Disorder

Background: The traditional cognitive-behavioral (CBT) model of obsessive-compulsive (OC) symptoms posits that the misappraisal of intrusive thoughts as meaningful results in obsessional anxiety and leads to compulsive rituals to reduce this anxiety. Yet this model does not entirely account for OC symptoms, and therefore it is useful to consider additional constructs which might add explanatory value. One prospect is the inference-based approach (IBA), which postulates that obsessions result from an inductive reasoning process termed "inferential confusion," which leads one to confuse a possibility with reality, and that vulnerable self-themes (e.g., fear of self) explain the heterogeneity of obsessions between individuals. The present study examined the traditional and IBA models as predictors of OC symptom dimensions. 

Method: Participants were 180 undergraduate psychology students who completed the Dimensional Obsessive-Compulsive Scale (DOCS), Obsessive Beliefs Questionnaire (OBQ-TRIP), Fear of Self Questionnaire (FSQ), Inferential Confusion Questionnaire (ICQ), and Depression, Anxiety, and Stress Scale (DASS-21). Correlations assessed bivariate relationships among variables. Hierarchical linear regressions predicted scores on each DOCS subscale: Contamination (DOCS-C), Responsibility for Harm (DOCS-R), Unacceptable Thoughts (DOCS-UT), and Symmetry (DOCS-S). DASS Depression scores were entered in Step 1, OBQ total scores in Step 2, and ICQ and FSQ total scores in Step 3.

Results: All study measures were significantly correlated (r = .169-.730). The final model predicting DOCS-C scores was significant, but the explained variance did not significantly increase with the addition of ICQ and FSQ scores (ΔR² = .017, p = .236). While OBQ scores emerged as a significant predictor in Step 2, no variables reached significance in the final model. The model predicting DOCS-R scores was significant, with OBQ and ICQ scores emerging as significant predictors. ICQ and FSQ scores accounted for an additional 7.0% of the variance in symptoms (p = .001). The regression predicting DOCS-UT scores was significant, with DASS Depression and FSQ scores emerging as significant predictors. The addition of ICQ and FSQ scores accounted for an additional 8.1% of the variance in symptoms (p < .001). The regression predicting DOCS-S scores was also significant. DASS Depression and ICQ scores were significant predictors. Together, ICQ and FSQ scores accounted for an additional 3.6% of the variance (p = .040).

Conclusions: Beyond what was explained by the traditional cognitive appraisal model, the IBA model contributed significant additional predictive value for symmetry, unacceptable thoughts, and responsibility for harm symptoms, but not contamination symptoms. Distinct elements of the IBA model predicted different symptom dimensions: inferential confusion seems to play a role in responsibility for harm and symmetry symptoms, and fear of self may help explain unacceptable thoughts symptoms. Future research should continue to explore how the IBA relates to OC symptom dimensions, including in a clinical sample.