Obsessive-compulsive spectrum conditions in obsessive-compulsive disorder and other anxiety disorders.

In light of current interest in an obsessive-compulsive spectrum of disorders, this study sought to determine whether comorbidity patterns support the unique relationship hypothesized between these conditions and obsessive-compulsive disorder (OCD). Comparisons were made of lifetime rates of several proposed spectrum conditions in individuals with one of three anxiety disorder principal diagnoses (OCD, social phobia, or panic disorder [PD], N=277). Spectrum conditions examined included tic-related disorders, trichotillomania, skin picking, and eating disorders, with analyses performed on rates both of clinical disorder alone, and clinical and subclinical manifestations jointly. The OCD group was found to differ from both other groups in showing 1) a greater proportion of individuals affected with any lifetime spectrum condition, 2) a greater number of lifetime spectrum conditions affecting each individual, and 3) a greater proportion of individuals having a lifetime history of multiple spectrum conditions. Analyses for specific spectrum conditions indicated differences among the anxiety disorder groups for all spectrum categories except eating disorders, though only in the case of tic-related conditions did OCD differ significantly from both comparison groups. For the other conditions, dissimilar patterns of differences were observed among the three groups, particularly when subclinical manifestations were included. These findings have conceptual and clinical implications, including 1) the salience of tic-related disorders in the OC spectrum, 2) the possibility that the relationship between spectrum conditions and anxiety disorders may take several different forms, and 3) the need for refinement of the hypothesized spectrum.