Neurobiological Background of Affective Disorders

Affective disorders, including major depression, mania and bipolar disorder, represent a spectrum of severe psychiatric diseases reflecting a continuum of psychopathological symptoms. Starting in young adulthood and often leading to suicidal ideation, affective disorders are ranking among the most disabling diseases worldwide in terms of the WHO global burden of disease, are socio-economically relevant, severe and prevalent. These diseases lead to enormous social disabilities due to affective and cognitive symptoms [1]. Depression, for example, has a lifetime risk of about 20-25% [2] and, besides suicide, a higher prevalence of the metabolic syndrome including coronary heart disease and diabetes increase mortality [3]. Bipolar disorder with manic episodes, in contrast, has a lifetime prevalence of about 1-5% [4]. However, due to the occurrence of depressive symptoms, the disease may be misdiagnosed Goldberg et al. [5] could show a hypo-manic or manic episode in 46% in patients with depression.