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 ordinarily 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.