Psychiatric disorders frequently compound the disability and complicate the management of neurologic conditions. These disorders result in increased morbidity for the person afflicted, stress for the caregiver, and financial burden. This study reviews the randomized double-blind placebo-controlled pharmacologic treatment trials of psychosis, depression, anxiety, and agitation in neurologic conditions from 1966 to 1998. Ten studies involving psychosis, 13 involving depression, and 20 involving anxiety-agitation meeting the committee's criteria were identified. Relatively few randomized double-blind placebo-controlled pharmacologic treatment trials of psychiatric disorders complicating neurologic disease have been conducted. These trials do not strongly support one specific pharmacologic approach to treatment. Further study of newer psychotropic agents, augmentation strategies, and novel use of other agents may help improve the treatment of psychiatric disorders observed in patients with neurologic disease.