Medical conditions with neuropsychiatric manifestations.

Medical disease sometimes affects patients through neuropsychiatric manifestations. When neuropsychiatric symptoms are predominant, identifying medical disease early in the illness course is imperative because many of these conditions are reversible with appropriate treatment. A high index of suspicion is required on the part of clinicians, particularly when patients also present with physical signs or unexplained symptoms that might suggest a broader, systemic process. The processes that most commonly cause neuropsychiatric symptoms include infectious, autoimmune, endocrinologic, metabolic, and neoplastic diseases. This article focuses on the most common of these conditions, and conditions for which early diagnosis and treatment are particularly important.