Although the treatment of obsessive-compulsive disorder (OCD) represents one of the most important achievements of psychopharmacology, even with the introduction of selective serotonin (5-HT) reuptake inhibitors (SSRIs) in clinical practice, about 30% of patients do not respond to standard therapeutic strategies. Herein, a comprehensive and critical review of pharmacological and other treatments commonly used in OCD is presented, with particular attention to resistance and predictors of response.
The PubMed (1980-2010) database was queried using the following key words: OCD, clomipramine, SSRIs, resistance, predictors of response, CBT, ERP, transcranial magnetic stimulation, deep brain stimulation, neurosurgery and ECT.
The 5-HT system is undoubtedly central to the pharmacological treatment of OCD, as demonstrated by the clinical effectiveness of serotonergic modulation. However, as numerous studies have revealed abnormalities in other neurotransmitter systems, neuropeptides and second messengers, it can be hypothesised that the heterogeneity of pathophysiological mechanisms may underlie the different clinical presentations and responses to treatment. Moreover, the latest developments in the pharmacology of SSRIs have shown that while they share the common property of 5-HT reuptake blockade, with the exception of citalopram and escitalopram, they nonetheless interact with other receptors and systems.
Although the treatment of OCD represents one of the major achievements of psychopharmacology of the last decades, there are still a number of problems that must be resolved in order to integrate this data with improved management of individual patients.