[Genetics of depression. Current knowledge and perspectives]

Depression is a common disorder (lifetime prevalence nearly 20% in industrialized countries) that presents in two etiologically different forms (unipolar depression, bipolar disorder). Both forms are subject to a genetic influence, which is stronger in bipolar disorder. Unipolar depression is also strongly influenced by nongenetic environmental factors (e. g., traumas, socialization, critical life events). There is strong evidence for a gene-- environmental interaction in unipolar depression. The search for genes was recently very successful in bipolar disorder. There is currently no evidence for disposition genes with strong effects. The prediction of response to selective serotonin-reuptake inhibitors (SSRI) by genetic markers presents currently the best confirmed molecular-genetic findings for unipolar depression. Complicating factors are gene--environmental interaction, only small to modest effects of disposition genes, and putative epigenetic mechanisms.