Epilepsy and obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) has long been associated with epilepsy The link with temporal lobe (usually refractory) epilepsy (TLE) is particularly prominent Of TLE patients, 10% to 22% of patients may have OCD, often underdiagnosed in the outpatient clinic. Data on the links include case reports, case series, and controlled studies. Three larger, controlled studies in TLE patients, using comprehensive epilepsy and OCD classifications, in aggregate, have noted the obsessive qualities of washing, symmetry/exactness, and ordering, with a greater preoccupation with certain aspects of religion, compared with controls or patients with idiopathic generalized epilepsy. TLE foci may be either left- or right-sided. Social and neurobiological factors are involved in OCD in TLE. The neurobiology implicates a pathophysiological or structural impairment of the orbitofrontal-thalamic, and fronto-thalamic-pallidal-striatal-anterior cingulate-frontal circuits. Discrete anatomic lesions in these pathways, or their surgical removal, may induce (or conversely) improve OCD in TLE patients.