Nineteenth-century neuropsychiatrists felt that the aged bipolar patient usually developed chronic mania, which eventually turned into dementia. The authors' elderly patients seemed to experience few such denouements, so they evaluated the course and treatment response of 81 bipolar patients over the age of 55. Fifty-six responded well to lithium. Advanced age had no effect on course or outcome. However, with increased clinical evidence of neurological illness there was an increased incidence of chronic mania, a poorer response to lithium, and more frequent and severe neurotoxicity. Extrapyramidal syndromes were particularly devastating.