To assess the efficacy and tolerability of quetiapine as add-on to antidepressant agents in treatment-resistant late-life major depression.

A group of 15 patients, 8 male and 7 female, mean age 68.2, evaluated in our department for clinical symptoms that made possible a DSM 5 diagnosis of major depressive disorder, were initiated on quetiapine XR, flexible daily dose 50–300 mg QD. All patients were on treatment with an antidepressant–either a selective serotonin reuptake inhibitor (SSRI) (n = 10), or venlafaxine (n = 5)–for at least 6 weeks and presented no improvement during current treatment administered at therapeutic doses. Patients were assessed using Montgomery Asberg Depression Rating Scale (MADRS), Clinical Global Impression–Severity (CGI-S), Global Assessment of Functioning (GAF), and Columbia Suicide Severity Rating Scale (C-SSRS) every 4 weeks for 3 months.

After 12 weeks, patients had a mean improvement in MADRS score of 45.7 ± 2.3%, with a final mean MADRS score of 13.5 (P < 0.01). No variations were registered depending on the specific SSRI or venlafaxine concomitant treatment. Quetiapine XR mean daily dose administered during the study was 125 mg. C-SSRS didn’t registered significant variations in suicidal ideation or behavior throughout the trial. Overall GAF score increased with 22.1 points, and CGI-S decreased with a mean of 1.5 points at week 12 (P < 0.01). Tolerability of add-on quetiapine was very good, no serious adverse event being reported.

Quetiapine was efficient and well tolerated in late-life resistant major depression, as add-on to SSRIs or venlafaxine, during the 12 weeks of the trial.