Neuropsychiatric Models of OCD

As recently as 15 years ago, obsessive-compulsive disorder (OCD) was considered a rare and untreatable illness. Now recognized as a severe, highly prevalent, and chronically disabling disorder affecting between 1% and 3% of the population worldwide (Rasmussen & Eisen, 1994), empirically supported cognitive-behavioral and pharmacological treatments are available for OCD (March & Leonard, 1998). The clinical phenomenology/nosology and empirical treatment for OCD have been well delineated across the life span in both children and adults, thereby making OCD a leading candidate for neurobiologic study. Specifically, OCD may be less vulnerable to ambiguities in expression across the lifetime (eg, in comparison to bipolar disorder and major depressive disorder). Investigations of OCD close to illness onset can then remain applicable to adult patients. Indeed, combining unique assessment/ treatment and neuroimaging/genetic expertise at specific performance sites has already resulted in substantial progress in understanding the brain mechanisms that may be involved in treatment response (or lack, thereof) (see Rosenberg & MacMillan, 2002 for review). A combination of expertise in technological and clinical disciplines provides an ideal forum for investigating mechanisms of treatment response in OCD.