Problems in diagnosing bipolar disorder in catatonic patients.

A bipolar patient presenting with catatonia may be misdiagnosed as having noncatatonic schizophrenia or unipolar depression because these conditions share the same signs. Of 12 patients with episodes of catatonia who were admitted to the authors' inpatient units, 8 were initially diagnosed as schizophrenic. Within 2 years, 8 of the 12 were ultimately diagnosed as suffering from bipolar affective disorder. Catatonia--a syndrome, not a diagnosis--seems more closely linked with bipolar disorder than with schizophrenia or unipolar depression.