Pharmacotherapy for obsessive-compulsive disorder (OCD) : predicting response and moving beyond serotonin re-uptake inhibitors

Clomipramine was seen as a breakthrough for sufferers of obsessive-compulsive disorder (OCD). When it was developed, it gave hope that a disorder that was viewed as untreatable could now be treated. Selective serotonin reuptake inhibitors (SSRIs) gave further hope that OCD could be treated without the adverse effects that are associated with clomipramine. Despite these advances, only approximately 10% of people suffering from OCD achieve symptom remission with pharmacological treatment. Studies of effectiveness often focus on symptom reduction (defined as either a 25% or 35% reduction in OCD symptom severity measured by the Yale-Brown Obsessive- Compulsive Scale [Y-BOCS]) and even then, only 40-60% of sufferers achieve symptom reduction with SSRI treatment. Response to non-pharmacological approaches to treating OCD, e.g. exposure and response prevention, appears to be similar, and although deep brain stimulation appears to hold promise, it also has a similar response rate in a more treatment resistant population of patients. Hence, there is a need to further investigate the factors that might be associated with treatment response. As many OCD sufferers are treatment resistant and treated with several pharmacological approaches, it is also important to study predictors of response to augmentation strategies.