Psychotic depression is a very difficult to treat psychiatric disorder with relatively poor prognosis for sustained remission. Antipsychotics are a mainstay of treatment but one question that has not been properly addressed is the requirement for extended treatment after an episode. A recent study was conducted to asses the effects of continuing antipsychotic medication once an episode of psychotic depression has responded to combination treatment with an antidepressant and antipsychotic agent. Conducted over 36 weeks and randomised, the trial conducted assessed adults with psychotic depression treated with sertraline plus olanzapine for up to 12 weeks and achieving remission of psychosis + remission or near-remission of depressive symptoms for 8 weeks before entering the clinical trial. Participants were randomly assigned to continue olanzapine (n = 64) or to switch from olanzapine to placebo (n = 62) in addition to sertraline. The main outcome assessed waas relapse, but secondary outcomes were change in weight, waist circumference, lipids, serum glucose, and HbA1c. The median sertraline dose was 150 mg daily and the median dosage of olanzapine was 15 mg daily. Thirteen participants (20.3%) randomized to olanzapine and 34 (54.8%) to placebo experienced a relapse (hazard ratio, 0.25; 95% CI, 0.13 to 0.48; P < .001). There were small but significant changes on some anthropometric and metabolic on some measures. Treatment with sertraline plus olanzapine compared with sertraline alone reduced the risk of relapse over 36 weeks. Read more detail about the study here