[Recent aspects of biological treatment of depression].

The problem of the so-called 'therapy-resistant depressions' or, as we prefer to say, 'depressions that are difficult to treat', is discussed. After paying particular attention to the infusion therapy, we deal with nonpharmacological treatments like sleep deprivation and light-therapy. Functional psychopathology and functional target syndromes, illustrated with the serotonin deficiency syndrome, are further topics. The use of low-dose high-potency neuroleptics in the treatment of affective disorders is covered. Finally, we point to the concept of 'neurasthenia' which seems to gain popularity anew.