(PS7-27) The Effect of Inverse Reasoning on Scrupulosity Symptoms

Abstract Text: Scrupulosity, a presentation of obsessive-compulsive disorder (OCD) that involves moral and religious themes, is associated with low insight (Tolin et al., 2001). The inference-based approach (IBA), a cognitive model that proposes OCD develops and is maintained by unhealthy reasoning processes, may be uniquely suited to treat OCD presentations with low insight (Visser et al., 2015). An unhealthy reasoning process identified by the IBA that may contribute to low insight is inverse reasoning, in which subjective inferences about reality are made without considering available evidence (O’Connor et al., 2005). Wong and Grisham (2017) found that experimentally inducing an inverse reasoning bias caused increased obsessive-compulsive (OC) symptoms, but research has not targeted the impact of inducing an inverse reasoning bias on scrupulosity symptoms. Based on the hypothesis that inverse reasoning is the mechanism that distorts otherwise healthy religious beliefs to scrupulosity symptoms, the current experiment aimed to determine whether inverse reasoning has a causal effect on scrupulosity symptoms.

Undergraduate participants (N = 108) were randomly assigned to either an experimental (n = 57) or control (n = 51) condition. Scrupulosity-specific versions of the Cognitive Bias Modification-Interpretation (CBM-I) and the Inverse Reasoning Task (IRT) utilized by Wong and Grisham (2017) were developed in consultation with Dr. Wong and Dr. Grisham for the current study. The CBM-I was designed to induce an inverse reasoning bias in the experimental condition and to not affect inverse reasoning in the control condition. The IRT was administered pre- and post-CBM-I; the Penn Inventory of Scrupulosity – Revised (PIOS-R) was administered post-CBM-I.

A 2 (condition: experimental, control) x 2 (time: pre-training, post-training) mixed ANOVA was conducted as a manipulation check. Results indicated that there was not a statistically significant two-way interaction between condition and time on IRT total scores (F(1, 105) = .08, p = .77)—evidence of an unsuccessful manipulation. As such, an independent samples t test revealed that PIOS-R scores (t(104) = 1.52, p = .13, d = .29) were not significantly different for the experimental (M = 62.93, SD = 16.63) and control (M = 58.06, SD = 16.49) conditions.

These results indicate that the CBM-I did not successfully induce an inverse reasoning bias among the experimental condition despite its similarity to the CBM-I utilized by Wong and Grisham (2017). Notably, the current study differed from Wong and Grisham (2017) in that it attempted to induce a scrupulosity-specific inverse reasoning bias. As such, inducing a bias toward inverse reasoning may be more difficult when utilizing scrupulosity-specific scenarios due to the moral implications of inducing such a bias. Further, participants may be less likely to believe corrective feedback that goes against their own beliefs, which may have led to less participant buy-in. Future research should investigate ways to successfully induce a scrupulosity-specific inverse reasoning bias and replicate the current study to examine whether inverse reasoning has a causal effect on scrupulosity symptoms.