A recent study by Levine and Leucht described several kinetics of treatment response among schizophrenic patients with antipsychotics. We aimed so to test this methodology in a population of depressed patients.

2938 outpatients with major depressive disorder were included in a multicentre, non interventional study, assessing at inclusion, week 2 and week 6, mood (QIDS-C, CGI, PGI and VAS) and functionality (SDS). To identify homogeneous groups of patients on the evolution of QIDS criteria over time (D0, W2 and W6), the latent class linear mixed model was used. Then, the groups were described at each time by several clinical characteristics and scores using ANOVA or the chi-square test. All metrics at day 0 and week 2 were tested for their capacity to predict a kinetic of response, all patients being treated by Agomelatine.

1200 patients were drug naïve for the current episode; 3 types of response kinetics were found: early, intermediate et late responders. The principal factor in relationship with a later response was the number of past episodes. Among the 1700 patients with a previous antidepressant treatment, 6 types of kinetics were distinguished: early response kinetics, intermediate and late response, non response and a singular one with early response at W2 and relapse at W6. The principal factor in relationship with a bad response kinetic was the age at first episode of mood disorder.

Previous reports stressing the interest of an assessment at week 2 were reinforced by the present results.