Mutism: review, differential diagnosis, and report of 22 cases.

Mutism is a common manifestation of both psychiatric and neurologic illness. Psychiatric disturbances associated with mutism include schizophrenia, affective disorders, conversion reactions, dissociative states, and dementias. Neurologic disorders producing mutism involve the basal ganglia, frontal lobes, or limbic system structures. In psychiatric and neurologic conditions, mutism is often associated with other signs of catatonia. The authors review the literature on mutism, including psychiatric, neurologic, toxic-metabolic, and drug-induced causes. Methods to discriminate among the many causes of mutism in the clinical setting are discussed, and 22 new cases of mutism are reported to emphasize the wide differential diagnosis.