ABSTRACT
What is schizophrenia? Since the term dementia praecox was coined by Kraepelin at the turn of the century, the precise answer to this question has remained stubbornly elusive (Meltzer & Liberman, 1982). In 1983 the World Psychiatric Association (WPA) published a compilation of 15 different sets of diagnostic criteria for schizophrenia (WPA, 1983). The criteria ranged from the work of Kraepelin and Bleuler to the Research Diagnostic Criteria (Spitzer, Endicott, & Robins, 1978) and DSM-III (American Psychiatric Association, 1980). The differences between the criteria demonstrated that for a complex disorder such as schizophrenia there is no single, universally accepted diagnostic schema. The clinical and research implications of this lack of agreement are considerable. For example, one study applied six different sets of diagnostic criteria for schizophrenia to the same 168 adult patients (Endicott et al., 1982). The rate of diagnosing schizophrenia varied as much as sevenfold, depending on which diagnostic criteria were used.
