Effect of lithium carbonate on lateralized cognitive functions

The effect of lithium carbonate on lateralized cognitive functions was studied by asking a patient suffering from a manic-depressive disorder to repeatedly recognize a given series of digits delivered dichotically while varying the dosage of lithium carbonate intake. The data showed that, whereas digit recognition from the right ear (left hemisphere) was about the same across tests, recognition from the left ear (right hemisphere) varied systematically with dosage variations. Specifically, it was found that an increase in dosage of lithium carbonate was associated with a decrease in recognition from the left ear. These data might indicate unilateral hemispheric effects of lithium carbonate on the dysfunctional right hemisphere of patients suffering from bipolar affective disorders. Clinical implications of the findings of the present case study are also discussed.