Antidepressant Medication and Executive Dysfunction: A Deleterious Interaction in Late-Life Depression

Objectives To determine whether there is differential response to placebo or citalopram among older patients with and without deficient response inhibition (DRI). Design This is an 8-week, double-blind, placebo-controlled trial. Setting Outpatient psychiatry. Participants Unipolar depressed patients aged 75 years and older. Intervention Citalopram (20-40 mg/day) or placebo pill. Measurements Baseline Stroop Color-Word Test and weekly 24-item Hamilton Rating Scale for Depression assessments. Results Citalopram-treated patients with DRI did significantly worse than placebo-treated patients with DRI. Conversely, citalopram-treated patients without DRI did significantly better than placebo-treated patients without DRI. Conclusion Patients with late-life depression and DRI respond worse to selective serotonin reuptake inhibitor (SSRI) than placebo. These findings suggest that there may be a deleterious interaction between DRI and antidepressant medication in late-life depression and that the mechanism of SSRI and placebo response is different.