Obsessive-compulsive disorder is a commonly occurring neuropsychiatric condition characterized by bothersome intrusive thoughts and urges that frequently lead to repetitive dysfunctional behaviours such as excessive handwashing. There are well-documented alterations in cerebral function which appear to be closely related to the manifestation of these symptoms. Controlled studies of cognitive-behavioural therapy techniques utilizing the active refocusing of attention away from the intrusive phenomena of OCD and onto adaptive alternative activities have demonstrated both significant improvements in clinical symptoms and systematic changes in (...) the pathological brain circuitry associated with them. Careful investigation of the relationships between the experiential and putative neurophysiological processes involved in these changes can offer useful insights into volitional aspects of cerebral function. (shrink)

APPENDIX: The data emerging from the clinical and brain studies described above suggest that, in the case of OCD, there are two pertinent brain mechanisms that are distinguishable both in terms of neuro-dynamics and in terms of the conscious experiences that accompany them. These mechanisms can be characterized, on anatomical and perhaps evolutionary grounds, as a lower-level and a higher-level mechanism. The clinical treatment has, when successful, an activating effect on the higher-level mechanism, and a suppressive effect on the lower-level (...) one. (shrink)