Background: Cognitive deficits associated with mood disorders, especially bipolar disorder, have been the focus of limited systematic investigation.
Methods: We tested 35 bipolar (21 in depressed state and 14 in mixed or manic state) and 58 nonbipolar depressed consecutively admitted young adult inpatients and 51 matched healthy individuals on the Cambridge Neuropsychological Test Automated Battery, a computerized neurocognitive battery.
Results: The mixed/manic bipolar patients demonstrated robust deficits in episodic and working memory, spatial attention, and problem solving. In contrast, depressed bipolar and nonbipolar patients demonstrated impairments only in episodic memory.
Conclusions: Neuropsychologic findings with the Cambridge Neuropsychological Test Automated Battery indicate widely distributed deficits in cognitive domains subserved by temporal, parietal, and frontostriatal systems in bipolar patients during mixed/manic states of illness. Significant deficits in bipolar and nonbipolar depressed patients were restricted to episodic memory, suggesting a more selective dysfunction in mesial temporal lobe function during episodes of depression. These findings highlight the different cognitive profiles of mania and depression, demonstrate similar patterns of neuropsychologic deficits in bipolar and nonbipolar depression, and point to a need for further research investigating the characteristics, causes, course, and treatment of severe cognitive deficits associated with mixed/manic phases of bipolar disorder.