Previous findings indicate increased concentration of pro-inflammatory cytokines in depression. A bidirectional relationship between depression and immunological alterations has been suggested: On the one hand pro-inflammatory cytokines may contribute to depression, on the other hand depression-linked changes (e.g. a reduction of activity, increased stress-sensitivity) may lead to increased secretion of pro-inflammatory cytokines. Therefore, this study is also supposed to investigate the influence of above mentioned interventions on pro-inflammatory cytokines. Using a waiting group, potential changes in psychometric and biological parameters without any intervention are controlled. Assessments take place at baseline, after 4 weeks of treatment, after 8 weeks of treatment, after 16 weeks of treatment and 6 months follow up.