Kraepelin and psychotic prodromal conditions.

When Emil Kraepelin combined the formerly distinct entities of dementia paranoides, catatonia and hebephrenia to form the concept of 'dementia praecox' in 1896, he was well aware that this new disease entity--first coined 'schizophrenia' by Eugen Bleuler in 1908--does not generally only start off with the first psychotic manifestation. Even in his original observations, the characteristic psychotic phenomena developed via transition sequences from rather uncharacteristic prodromal disturbances. Meanwhile an initial prodromal condition was shown for about 75% of first-episode psychosis patients, lasting 5 years on average, possessing pathological significance and leading to psychosocial disruptions. Whereas most symptoms of the initial prodromal condition appear to be rather unspecific and hard to distinguish from other psychiatric conditions especially depressive ones, some syndromes seem to enable an early detection and thus an indicated prevention. These are constituted by attenuated and/or transient psychotic symptoms on the one hand and certain cognitive-perceptive basic symptoms on the other. Whereas the former are thought to delineate an advanced prodromal state, the latter can occur early in course and even at the beginning of the transition sequence to first-rank symptoms. This review will outline the current state of the art of a phase specific early detection and intervention based on these syndromes.