[Nature meets nurture: the importance of epigenetics for the aetiology of psychiatric diseases].

A successful therapy requires an understanding and investigation of the aetiology of a disease. Psychiatric diseases represent a special challenge, because environmental factors may play a crucial role in their development as well as possible physiological and genetic causes. Therefore, epigenetics has established itself to be a branch of research that studies the effect of environmental factors on the development of psychiatric diseases, leading to promising new approaches for diagnosis and therapy.