The identification of OCD-related subgroups based on comorbidity

Background Individuals with obsessive–compulsive disorder (OCD) frequently have other psychiatric disorders. This study employed latent class analysis (LCA) to explore whether there are underlying clinical constructs that distinguish “OCD-related” subgroups. Methods The study included 450 subjects, case and control probands and their first-degree relatives, and LCA was used to derive empirically based subgroups of 10 disorders: OCD, obsessive–compulsive personality disorder (OCPD), recurrent major depressive disorder (RMDD), separation anxiety disorder, panic disorder or agoraphobia (PD/AG), tic disorders (TD), generalized anxiety disorder (GAD), somatoform disorders (hypochondriasis or body dysmorphic disorder), pathologic skin picking or nail biting (PSP/NB), and eating disorders (EDs). The derived classes were compared on several clinical variables. Results The best fitting model is a four-class structure: minimal disorder, predominant RMDD and GAD, “highly comorbid,” and PD/AG and TD. The nature and number of disorders represented suggests that the first classes are distributed ordinally on a dimension of severity, and the fourth class is qualitatively distinct. Support for this structure is based on the number of disorders, age at onset of OCD, neuroticism, and extraversion. Conclusions In this OCD enriched sample, LCA identified four classes of disorder. These classes appear to conform to two subgroups that may prove useful in investigating the etiology of OCD.