Obsessions appear after the removal a brain tumor in the right frontal lobe.

A series of case reports and neuroimaging research points to the underlying neuropathological substrate for obsessive-compulsive disorder (OCD) and the underlying associations between OCD and areas of the frontal lobe. We report a patient wherein the onset of OCD occurred after resection of meningioma of the right frontal lobe and who was treated successfully with paroxetine hydrochloride. We suggest that the onset of secondary (organic) OCD is associated with the frontal lobe, and we propose that the origin of obsessions is located in the right frontal lobe.