Serotonin-1D hypothesis of obsessive-compulsive disorder: an update.

Support for the serotonin-1D (5-HT(1D)) hypothesis of obsessive-compulsive disorder (OCD) and related conditions comes from a variety of sources. Some pharmacologic challenges with the 5-HT(1D) agonist sumatriptan, and case reports in which prolonged administration of 5-HT(1D) agonists was associated with a therapeutic effect, suggest that 5-HT(1D) may play a role in obsessive-compulsive symptoms. Genetic studies have also found that polymorphism of the 5-HT(1D) gene may be preferentially transmitted to those patients with OCD. However, taking into account that OCD is a heterogeneous syndrome, the 5-HT(1D) hypothesis requires further investigation in order to disentangle the role of the 5-HT(1D) receptor in this common and often severe disorder.