Impact of duration of antidepressant treatment on the risk of occurrence of a new sequence of antidepressant treatment.

INTRODUCTION Despite the recommendation that antidepressant treatment should be continued for several months to reduce the risk of relapse/recurrence of depression, early discontinuation is frequent in naturalistic conditions. The study was aimed at exploring the impact of early discontinuation of antidepressant treatment on the risk of antidepressant re-initiation. METHODS A follow-up study of persons (n=35,053) starting antidepressant treatment was performed using a representative sample of the French Social Security Insurance national database. RESULTS The risk of re-initiation of antidepressant treatment was higher if the duration of the index episode of antidepressant treatment was ≥ 6 months [hazard ratio (HR)=2.35; 95% CI 2.25-2.45) or 2-5 months (HR=1.65; 95% CI 1.59-1.71) compared to ≤ 1 month. The other characteristics independently associated with re-initiation of treatment were older age, female gender, low income, serious chronic illness, index prescription by a specialist and co-prescription of other psychotropic drugs. CONCLUSIONS The lower risk of re-initiation of antidepressant treatment in persons with shorter-than-recommended duration of antidepressant treatment might be explained by overprescription of antidepressants in persons with sub-threshold symptoms.