Over the last 25 years, the perception of obsessive-compulsive disorder (OCD) has changed; where once it was seen as a rare refractory disorder, it is now viewed as a fairly prevalent, but treatable, medical condition responding to two main therapeutic strategies–serotonin reuptake inhibitors (SRIs) and cognitive-behavioral therapy (CBT). Given the emergence of new results with SRIs, more data on the role of augmentation strategies with second-generation antipsychotics, and recent genetic and neuroimaging findings with potential for advancing the understanding of the pathogenesis of OCD, it was thought appropriate to revisit OCD in order to identify key developments in this field and examine how they might be translated into the clinical arena. This consensus statement is the product of the International Anxiety Disorders Conference that took place in Cape Town in February 2006, and is referred to as the Cape Town Consensus (CTC).

In the Diagnostic and Statistical Manual of Mental Disorders (DSM) system, OCD has been classified as an anxiety disorder. However, in the International Classification of Diseases (ICD) system, OCD is separated from these conditions. This is consistent with several findings. OCD can begin before puberty, whereas other anxiety disorders, particularly generalized anxiety disorder (GAD), have a later age of onset. OCD is similarly prevalent in men and women, as opposed to depressive and anxiety disorders, which are more common in women. Pharmacologic challenges in some (but not all) studies show exacerbation of symptoms to 5-HT receptor agonists (eg, mCPP, sumatriptan), but not to other anxiogenic challenges such as yohimbine, sodium lactate, caffeine, CO2, cholecystokinin, and pentagastrin, which are known to elicit anxiety symptoms in anxiety disorders.