The group of acute psychoses in later life comprises: 1. acute psychotic pictures at the commencement or during the course of organic breakdown; 2. strictly speaking exogenous (symptomatic) psychoses 3. acute psychotic conditions during the processes in particular of endogenous psychoses; and 4. psychoreactive and situationally conditioned psychoses. In all these nosologically heterogeneous forms certain characteristics regarding their appearance and course can be perceived which are related to age a rudimentary type of syndromic pictures, their particular "senile" colouration, a preponderance of short and recurrent psychotic periods, a not infrequent change to dementia, and the occurrence of illnesses typical of old people (amnestic states of disorientation, complete optical illusions, etc.). The outlook for acute psychoses in later life is gloomy (almost 50% fatality); the recognition of basic illnesses causes particular difficulties. Some special clinical forms are being more intensively analysed.