A comparison of insight in body dysmorphic disorder and obsessive-compulsive disorder

Insight/delusionality of beliefs is an important dimension of psychopathology across psychiatric disorders. This construct is of increasing interest in obsessive-compulsive and related disorders, including obsessive-compulsive disorder (OCD) and body dysmorphic disorder (BDD). Even though OCD and BDD are considered closely related, no prior study has compared these disorders across a range of categories of global insight (excellent, good, fair, poor, absent/delusional), and only one study has compared these disorders on individual components of insight. Using the reliable and valid Brown Assessment of Beliefs Scale (BABS), this study examined insight/delusionality of OCD- or BDD-related beliefs in 211 individuals with primary OCD versus 68 individuals with primary BDD. In both disorders, levels of insight spanned the full range, from excellent to absent (i.e., delusional beliefs). However, the distribution of BABS scores across insight categories differed significantly by disorder, with the majority of OCD subjects showing excellent or good insight, and the majority of BDD subjects showing poor or absent insight. Compared to OCD subjects, BDD subjects had significantly poorer insight both overall (total BABS score) and on all individual BABS items. BABS score was significantly correlated with BDD and OCD severity, but in regressions it accounted for only 21% of the variance in OCD and 28% in BDD. In summary, both global insight and its individual components are poorer in BDD than in OCD, which has implications for research and clinical care, as well as understanding of the relationship between these disorders. Disorder severity is associated with but not equivalent to insight/delusionality.