Symptom dimensions in obsessive-compulsive disorder: implications for the DSM-V.

In the absence of definitive etiological markers of vulnerability or a unitary profile of pathophysiology for obsessive-compulsive disorder (OCD), obsessive-compulsive (OC) symptom dimensions seem to offer a fruitful point of orientation. The complex clinical presentation of OCD can be summarized using a few consistent and temporally stable symptom dimensions. These can be understood as a spectrum of potentially overlapping features that are likely to be continuous with "normal" worries and extend beyond the traditional nosological boundaries of OCD. Although the understanding of the dimensional structure of obsessive-compulsive symptoms (OCS) is still imperfect, this quantitative approach to phenotypic traits has the potential to advance our understanding of OCD and may aid in the identification of more robust endophenotypes. Preliminary data suggest that these dimensional phenotypes may be useful in studies of the natural history, genetics, neurobiology, and treatment outcome of OCD. A dimensional approach is not mutually exclusive of other methods to parse the larger spectrum of disorders related to OCD. Thus far, age-of-onset of OCS and the individual's "tic-related" status seem to be particularly useful categorical distinctions. Finally, existing assessment methods are inadequate and new dimensional scales are needed to take full advantage of a dimensional approach in clinical and population-based studies.