Included in the early definitions of the disease, both of Kraepelin and of Bleuler, were a characteristic premorbid personality, an insidious onset of the more flagrant symptoms in adolescence or early adult life, and a chronic but fluctuating course with a tendency to progressive deterioration. Both of these early investigators regarded hallucinations and delusions as secondary symptoms that could be absent, as in their category of “simple schizophrenia.” Embodied in both their definitions was the concept of disease characterized by a poor prognosis and, as stated earlier, a unique constellation of symptoms different from those of delirium, confusion, depression, mania, and dementia—which are manifestations of brain diseases. Many of their seminal ideas, and others discussed below, have been retained but most have been discarded in modern diagnostic criteria. Nonetheless, they established a lexicon for the clinical description and grading of schizophrenic disorders and all subsequent progress has been essentially to refine these ideas. For that reason, they are summarized here so that the student may appreciate the evolutionary nature of diagnostic criteria, as expressed through the DSM, currently in its fifth recursion.
Attempts to apply the early criteria initially met with difficulty, especially when hallucinations and delusions were absent. To overcome this, Schneider proposed that the distinction between primary and accessory manifestations be abandoned. He attached more importance and reliability to the occurrence of auditory hallucinations, perceptual delusions (misinterpretation of what the patient hears and feels), and disturbances of thinking (experiences of alienation and influence). This constellation of symptoms, which was more precise and easy to recognize, came to be known as Schneider’s first-rank symptoms of active schizophrenia. The Schneider’s diagnostic criteria, when applied to a group of patients admitted to the hospital with a diagnosis of schizophrenia, served to distinguish those with better and worse prognosis (Taylor). Those without hallucinations, delusions, and thought control or projection responded more poorly to treatment and required a more prolonged period in the hospital and higher doses of neuroleptic drugs than did those with these features. The 2 groups correspond closely to two categories of schizophrenic disorders later separated by Robins and Guze on the basis of prognosis. The Schneider-positive, poor-prognosis schizophrenia (also referred to in older literature as nuclear or process schizophrenia) corresponded closely to kraepelinian schizophrenia, while many of the Schneider-negative patients with good prognosis were probably suffering from some other nonschizophrenic illness such as bipolar disease (see Chap. 48). Having made these comments, it must be acknowledged that newer classifications of schizophrenia gives these distinctions less credibility and points to marginal differences in outcome and responses to treatment.
Feighner and colleagues, who drew up a set of diagnostic criteria for research in the major psychiatric syndromes (which were subsequently incorporated, until recently, into successive editions of the Diagnostic and Statistical Manual of Mental Disorders [DSM]), stated that the diagnosis of schizophrenia is tenable only in the presence of (1) a chronic illness of at least 6 months’ duration and a failure (after an acute episode) to return to the premorbid level of psychosocial adjustment, (2) delusions or hallucinations without significant confusion or disorientation (i.e., without clouding of consciousness), (3) verbal productions that are so illogical and confusing as to make communication difficult (if the patient is mute, diagnosis should be deferred), and (4) at least three of the following manifestations: (a) among adults, the lack of a partner or spouse; (b) poor premorbid social adjustment or work history; (c) family history of schizophrenia; or (d) onset of illness prior to age of 40 years. Important exclusions from certainty in the diagnosis of schizophrenia include the absence of a family history of bipolar disease, absence of an earlier illness with depressive or manic symptoms, and absence of alcoholism, drug abuse, or other organic disease.