Manic pseudodementia: case report.

The case of a 48-year-old woman hospitalized with a diagnosis of organic brain syndrome and later diagnosed as manic-depressive is presented to illustrate the occurrence of pseudodementia in bipolar illness. The patient's cognitive impairments and their response to lithium carbonate treatment were documented by clinical observation and neuropsychologic testing. This case raises the possibility that a preexisting subclinical neurologic disorder may contribute to the presentation of functional psychiatric illness as pseudodementia.