There is still a lack of controlled outcome and follow-up studies about the role of adjuvant psychotherapy in Bipolar Disorder. By treating older subjects having suffered of multiple affective episodes, the potential benefit of psychotherapy to prevent relapse and help to adjust to this chronic illness might be underestimated. In addition, the investigators have no knowledge of mechanism (mediators) of positive changes by successful psychotherapy and of subjects with good outcome of adjuvant psychotherapy (moderators, indicators, predictors). Possible mediators and moderators can be sociodemographic, psychological (cognitive, interactional), and/or biological (neuronal, genetic). The planned study will address all three areas of questions. In a multi-center study, 300 younger subjects suffering of a Bipolar Disorder will be included and provide with one of two treatments in addition to stable medication. Moderators and mediators are selected on promising preliminary results and based on a psycho-biological understanding of Bipolar Disorder.