Delirium is the most common acute organic psychosis, which occurs more
frequently in the elderly. The mortality is high. Nevertheless, the k
nowledge of delirium is limited because the lack of intensive research
on delirium. In this report the recent literature is reviewed with sp
ecial regard to psychopathology, pathogenesis, epidemiology, diagnosti
cs, and therapy. There is no uniform pathogenesis. Imbalance of neurot
ransmitters, hormones and electrolytes are probably important factors
in the pathogenesis of delirium. However, the relationships are very c
omplex and remain to be elucidated. Probably rebound phenomena play a
role in the development of deliria due to substance withdrawal. In bra
in or somatic disorders cerebral metabolic changes are believed to be
the main cause of delirium.