Schizophrenic patients occupy about half the beds in psychiatric hospitals—more hospital beds than are allocated to any other single disease—and they constitute 20 to 30 percent of all new admissions to psychiatric institutions (100,000 to 200,000 new cases per year in the United States). The age of admission generally is between 20 and 40 years, with a peak between 28 and 34 years. The economic burden created by this disease is enormous—the direct and indirect costs in the United States have been estimated to be over $50 billion.
Neurologists and psychiatrists currently accept the idea that schizophrenia comprises a group of closely related disorders characterized by a particular type of disordered thinking, affect, and behavior. The syndrome by which these disorders manifest themselves differs from those of delirium, confusional states, dementia, and depression in ways that will become clear in the following pages. Unfortunately, the diagnosis of schizophrenia depends on the recognition of characteristic psychologic disturbances largely unsupported by physical findings and laboratory data. This inevitably results in a certain degree of diagnostic imprecision. In other words, any group classified as schizophrenic will include patients with diseases that only resemble schizophrenia, whereas variant or incomplete cases of schizophrenia may not have been included. Moreover, there is not full agreement as to whether all the conditions that are called schizophrenic are the expression of a single disease process. In the United States, for example, paranoid schizophrenia is usually considered to be a subtype of the common syndrome, whereas in some parts of Europe it is thought to be a separate disease.
Present views of the disease now called schizophrenia originated with Emil Kraepelin, a Munich psychiatrist, who first clearly separated it from bipolar psychosis. He called it dementia praecox (adopting the term introduced earlier by Morel) to refer to a deterioration of mental function at an early age, from a previous level of normalcy. At first, Kraepelin believed that “catatonia” and “hebephrenia,” which had previously been described by Kahlbaum and by Hecker, respectively, as well as the paranoid form of schizophrenia, were separate diseases, but later, by 1898, he had concluded that several subtypes were a single disease. He emphasized an onset in adolescence or early adult life and a chronic course, often ending in marked deterioration of personality as the defining attributes of all forms of the disease. Early in the 20th century, the Swiss psychiatrist Eugen Bleuler substituted the term schizophrenia for dementia praecox. This was an improvement insofar as the term dementia was already being used to specify the clinical effects of another category of disease; unfortunately, however, the new name implied a “split personality” or “split mind.” By the “splitting” of psychic functions, Bleuler meant the lack of correspondence between ideation and emotional display—the inappropriateness of the patient’s affect in relation to his thoughts and behavior. In contrast, in bipolar disease, the patient’s mood and affect accurately express his morbid thoughts. Bleuler also introduced the term autism (“thinking divorced from reality”) as an aspect of the thought disorder.
Bleuler believed that all the schizophrenic syndromes were composed of primary or basic symptoms, summarized by subsequent authors as the “four A’s” (loose associations, flat affect, ambivalence, and autism) and of secondary or “partial phenomena” such as delusions, hallucinations, negativism, and stupor. However interesting this formulation proved to be, the psychologic abnormalities are so difficult to define precisely that these divisions have come to be of only mnemonic value.