Clinical Vignette:

A 59-year-old man was found dead from a self-inflicted gunshot wound. Three years before his death he developed left-sided hemianesthesia. A computed tomographic (CT) scan taken at the time showed a lesion in the tegmentum of the upper pons of the right side. Over the following few months, further neurological deficits developed, but he was not incapacitated. Five months after the initial episode severe depression with paranoid ideations developed. The patient had no past or family history of affective disorders. He failed to respond to a number of antidepressants that were tried over a period of 2 years. Postmortem examination revealed a cavernous hemangioma impinging on the upper pontine region of the raphe nuclei on the right side and extending to partially involve the raphe on the left side. It was believed that the lesion caused depletion of the ascending serotonergic system to the forebrain (Kline and Oertel, 1997).