As there are drugs with proven efficacy for recurrent depressive disorders, such as lithium, we are keen to know why the authors did not try to compare the efficacy of sertraline with existing drugs. It appears that the authors were keen to reflect a drug-specific effect rather than demonstrating its relative efficacy. As readers, we would like to know why the authors carried out such a long placebo phase (2 months). The patients were left without any medication for 2 months, and during this phase, all the potential patients who were more likely to have relapsed were dropped from the study. Sixty-one subjects (16%) discontinued treating during this phase. It clearly raised doubts as to whether the authors introduced bias at this stage by using an open placebo arm for 2 months. Additionally, the authors restricted the inclusion criteria and excluded depressed patients who had anxiety. However, in day-to-day clinical practice, we have a large proportion of patients who have depression with anxiety. The results of this study may not be applied to this group of patients. In light of these issues, it will be unreasonable to conclude that sertraline is significantly effective in the preventive recurrence of depression compared to placebo.