Performance on tasks tapping automatic and voluntary aspects of memory, attention, and motor speed was examined in 14 patients with major depressive disorder, before and after 3 weeks of treatment with clomipramine (150 mg/day), a potent serotonin and noradrenaline uptake blocker with anticholinergic side effects. Performance on tasks requiring frontal functions improved or did not change, whereas verbal learning and retention, where hippocampal functioning is critical, were impaired. The latter tasks were negatively related to cerebrospinal fluid (CSF) 5-HIAA levels and plasma concentration of clomipramine. The results provide further support for the regulatory role of monoaminergic systems in cognition. Furthermore, we found the automatic-voluntary capacity distinction less heuristically useful. Physiological mechanisms regulating different aspects of cognition and memory appeared to be more closely related to the type of task used than to its capacity-demanding properties.