[Seasonal affective disorders]

In 1984 Rosenthal described for the first time the syndrome "Seasonal Affective Disorder", SAD, characterized by annual recurrent depressive episodes in the autumn and winter months possibly followed by mania/hypomania in the summer months. The depressive phases showed atypical symptoms such as hypersomnia, carbohydrate-craving, and weight gain. Melatonin seems to be an indicator of disturbed circadian rhythm rather than the cause of SAD. The importance of other circadian and annual biological rhythm in relation to SAD and other depressive syndromes is quite unknown. SAD differs from classical manic-depressive disorders by frequency, severity, symptomatology, and the typical seasonal variations, and is probably not a subgroup of the classical affective disorders, but an extreme variation of the normal seasonal affective variations seen in the general population. Light therapy can be used successfully in depressive states in SAD.