Cerebral laterality and depression: relations of perceptual asymmetry to outcome of treatment with tricyclic antidepressants.

The relationship of cerebral laterality to outcome of treatment with antidepressants was examined by comparing perceptual asymmetry in subgroups of depressed patients formed on the basis of clinical response to a tricyclic antidepressant (TCA) or a monoamine oxidase inhibitor (MAOI). Perceptual asymmetries of 63 unmedicated depressed patients were assessed for verbal and nonverbal tasks, using dichotic listening and visual half-field methods, and retests were obtained on 49 patients after about 6 weeks of treatment. There were significant differences between TCA responders and TCA nonresponders in dichotic listening and visual field asymmetries. Differences in perceptual asymmetry were specific to TCAs, in that no comparable differences existed between MAOI responders and MAOI nonresponders. Although perceptual accuracy improved following successful TCA treatment, abnormal perceptual asymmetries in TCA responders were present before and after treatment and may thereby represent state-independent characteristics.