Diagnosis and lithium treatment of affective disorder in the retarded: five case studies.

The authors report on five institutionalized retarded patients who had symptoms strongly suggestive of manic-depressive illness and who showed significant symptom reduction in a single-blind placebo-controlled three-year trial of lithium. The number of illness episodes was reduced, and symptoms decreased in all major illness dimensions. These findings indicate that major affective disorder can be both diagnosed and treated in individuals with primary mental retardation.