COMORBIDITY OF MOOD DISORDERS - A LONGITUDINAL PROSPECTIVE-STUDY

From the Zurich cohort study (n = 591), the association of major depre ssive episodes and recurrent brief depression (RED) with other psychia tric disorders is presented cross-sectionally at age 28 and 30 years, and over ten years (age 20 to 30 years). Longitudinally, the odds rati os of major depression are highest with dysthymia (4.4), generalised a nxiety disorder (4.4), panic disorder (2.7), hypomania and agoraphobia (2.6), and social phobia (2.4). There is a significant association wi th cannabis consumption and smoking. Follow-up data over nine years ar e available for 41 patients with a major depressive disorder (MDD) and 62 with RED: approximately 20% of MDD patients did not receive a diag nosis during follow-up. Major depression reoccurred in 32%, became bip olar in 24%, or developed into RED in 24%. RED remitted in 41%, reoccu rred in 35%, turned into major depression in 22%, and became bipolar i n only 7%. Longitudinally, MDD and RED show a symmetrical diagnostic c hange in a quarter of the cases. There is no substantial development o f MDD or RED into minor depression or generalised anxiety disorder. Th irteen per cent of those with RED later developed panic disorder.