Symptom Dimensions in OCD: Developmental and Evolutionary Perspectives

At the present time, in the absence of definitive etiological markers of vulnerability for obsessive-compulsive disorder (OCD), obsessive-compulsive (OC) symptom dimensions appear 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 vulnerabilities that are likely to be continuous with “normal” worries and extend beyond the traditional nosological boundaries of OCD. Although the dimensional structure of OC symptoms 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 also appears to be congruent with evolutionary and developmental perspectives on OCD. This view point posits that each symptom dimension reflects the dysregulation of highly conserved complex and partially overlapping neural systems that serve to detect, appraise, and respond to potential threats. A dimensional approach is also not mutually exclusive of other methods to parse the larger spectrumof disorders related to OCD. Indeed, the combined use of categorical subtypes and dimensional assessments are likely to offer the greatest promise. Thus far, age-of-onset of OC symptoms and the individual's “tic-related” status appear to be particularly useful categorical distinctions.