The Genetics of MDD – A Review of Challenges and Opportunities

Abstract

Major depressive disorder (MDD) is a psychiatric disorder characterized among others by prolonged depressed mood, a loss of interest in enjoyable activities, psychomotor retardation and various cognitive symptoms. Although exact numbers of prevalence may differ between various western countries, partly due to a social taboo of the illness, the lifetime prevalence in the USA and Western Europe lies around 15%. Women are more likely to be struck by MDD than men, often with a first episode between 30-40 years of age, with a smaller second peak around 50-60 years of age. Although MDD may appear as a "stand alone" disease, 33% of patients with a chronic illness report symptoms of major depression. In addition, approximately 72% of patients diagnosed with MDD also have a second mental illness diagnosed, in most cases generalized anxiety disorder or a social phobia. Although some patients may only experience a single episode, MDD often appears in multiple episodes.