The possible effects of clinical depression on intellectual function were investigated in unipolar and bipolar patients. Ninety-six hospitalized depressed patients completed the Wechsler Adult Intelligence Scale (WAIS) on admission and 34 were retested on remission. The high average full scale IQs found remained relatively stable throughout, consistent with earlier studies indicating a limited relationship between intellectual function and clinical severity of depression. No evidence was found for retarded psychomotor activity in bipolar groups or increased psychomotor activity in unipolar groups on three WAIS subtests of psychomotor function, but full scale IQ increased slightly in hypomania.