Abstract
Obsessive-compulsive disorder (OCD) is a clinical syndrome whose hallmarks are
excessive, anxiety-evoking thoughts and compulsive behaviors that are generally
recognized as unreasonable, but which cause significant distress and impairment.
When these are the exclusive symptoms, they constitute uncomplicated OCD. OCD
may also occur in the context of other neuropsychiatric disorders, most commonly
other anxiety and mood disorders. The question remains as to whether these
combinations of disorders should be regarded as independent, cooccurring
disorders or as different manifestations of an incompletely understood
constellation of OCD spectrum disorders with a common etiology. Additional
considerations are given here to two potential etiology-based subgroups: (i) an
environmentally based group in which OCD occurs following apparent causal events
such as streptococcal infections, brain injury, or atypical neuroleptic
treatment; and (ii) a genomically based group in which OCD is related to
chromosomal anomalies or specific genes. Considering the status of current
research, the concept of OCD and OCD-related spectrum conditions seems fluid in
2010, and in need of ongoing reappraisal.