Neuroleptic dose and desipramine concentrations during combined treatment of unipolar delusional depression.

The relationship of response to neuroleptic dose and desipramine plasma concentration was examined in 31 patients with unipolar delusional depression. The patients received either perphenazine or haloperidol for 1-2 weeks, after which desipramine, 2.5 mg/kg of body weight per day, was added. Neuroleptic dose varied among patients but was constant within individuals. Global response was rated retrospectively on the basis of outcome during the fourth week of combined drug treatment. Responders had higher plasma desipramine concentrations and had received higher neuroleptic doses than nonresponders had. The effective threshold level for desipramine was similar to that previously described for nonpsychotic melancholic patients, suggesting a similar mode of action for the drug in the two disorders.