 Preliminary data suggest that depressed patients with increased left hemispheric laterality of perceptual processing are unlikely to improve during 6 weeks treatment with placebo, while being very responsive to either imipramine or fluoxetine. Depressed patients who do not show evidence of poor right hemispheric functioning respond significantly more often to placebo than those with poor right hemispheric functioning , and do not show an advantage of drug over placebo. 100 patients will be tested with verbal and nonverbal dichotic tests, and then treated sequentially with bupropion, escitalopram, and imipramine. Preferential hemisphere for auditory processing will be correlated with treatment outcome. 