Comparative adherence to antidepressant drugs in a non-psychiatric outpatient clinic setting in Japan

Premature discontinuation of antidepressant treatment is associated with an increased risk of relapse. There is, however, little evidence concerning comparative discontinuation rates of different classes of antidepressants such as tricyclic antidepressants, selective serotonin reuptake inhibitors, and atypical antidepressants such as sulpiride. We have studied the adherence to different antidepressant treatments during the early treatment phase. Over a 10-month period, a total of 265 outpatients, who were prescribed one or more antidepressants in a psychosomatic medical department of a Japanese University Hospital, were enrolled for study. The subjects were generally suffering from mild to moderate depression. The adherence to antidepressant medication was observed during the initial 13 weeks of treatment. The data were analysed using Kaplan-Meier method and Cox proportional hazards model. The overall adherence to antidepressants over the initial 13 weeks was 66.8%. Among the antidepressants used, the adherence to sulpiride was the best (87.6%), followed by maprotiline (76.6%) and clomipramine (66.9%). The adherence to sulpiride was statistically significantly greater than the other antidepressants employed. It is suggested that sulpiride is particularly suitable for use in the psychosomatic medical setting in Japan and probably elsewhere.