Early prediction of the effectiveness of antidepressants: inputs from an animal model.

Although depressive disorders affect approximately 5% of the population in developed countries each year, current antidepressants usually require several weeks to produce beneficial clinical effects and are only effective in about 55% of patients. Therefore, early prediction of the effectiveness of a particular antidepressant for a patient is important for effective pharmacological treatment of depression. In this study, we examined a new method, based on mathematical analyses, of exploratory behavior for predicting the effectiveness of particular antidepressants shortly after initiation of treatment. By using this method, we were able to predict the effectiveness of antidepressants 1-3 days after initiation of treatment in individual subjects.