[Early and intermediate responses as factors predicting efficiency of antidepressive agents]

An important limitation in the treatment of depression is the lack of reliable factors for predicting treatment response. Most of these factors have been related to biological and clinical aspects. A clinical aspect that has proved to reasonably predict long-term efficacy is early response. An adequate early response predicts a good outcome at the long term. The purpose of this study was to quantify the proportion of patients who show no response to a fixed dose of antidepressants after 2,4, and 6 weeks of treatment, and then respond by week 8. Additionally, a subgroup of patients was followed using the same methodology until 12 weeks of treatment. A lack of response by weeks 4 and 6 predicted a final lack of response both at weeks 8 and 12 of treatment. Alternatively, a robust response as early as week 2 predicted a good response by the end of the two treatment periods. These findings should help clinicians revalorate treatment when finding no response after 4 or 6 weeks of treatment.