Neuropsychology of schizophrenia according to Kraepelin: disorders of volition and executive functioning.

Emil Kraepelin was the first to identify schizophrenia as a distinct disease in 1896. The purpose of this paper is to rediscover and reexamine the neuropsychology of schizophrenia according to Kraepelin. Kraepelin thought that the "dementia" of dementia praecox was primarily a disorder of volition, rather than one of intellect. "Volition" or "will" referred to the ability to make conscious decisions and to carry them out. By quoting relevant passages in his classic textbook, Dementia Praecox and Paraphrenia, the case is made that Kraepelin's detailed description of volitional deficits in patients with dementia praecox clearly documents impairments in executive functioning in schizophrenia patients during the preneuroleptic era. To a large extent, these deficits may be responsible for the "dementia" of dementia praecox and the "chronicity" of chronic schizophrenia. If this hypothesis is correct, the long-range prognosis of patients with schizophrenia may be considerably improved by treatment programs designed to facilitate executive functioning.