[Biological bases of obsessive-compulsive disorder]

Obsessive Compulsive Disorder, combines several characteristics which suggest an organic etiopathology. The evidence relies on: genetic studies; the treatment response to drugs with serotonergic profile; the appearance of obsessive-compulsive disorder after cerebral nervous system damages; the existence of neurophysiological alterations; good response to neurosurgery and negative course evaluation. In spite of all, the studies of the biological bases of the Obsessive-compulsive Disorder are scarce, which perhaps can be explained due to its relatively low incidence. The present paper reviews all available studies in this area, those referred to family predisposition, dysfunctions of neurotransmission systems, specific biological markers or those common to depression and the most recent research (including new brain imaging techniques) on organic etiology of this disorder.