Virtually all descriptions of schizophrenia place heavy emphasis on thought disorder as a primary feature of the disorder. Relying on observations of schizophrenics' verbal behavior, Bleuler (1950), for example, postulated that a "loosening of associative threads" was the most important feature of the disorder. Bleuler's view has heavily influenced the definition of schizophrenia as it now appears in the American Psychiatric Association's Diagnostic and Statistical Manual (DSM-II) and the forthcoming DSM-III. Kurt Schneider (1959), whose writings have had a greater impact on European definitions of schizophrenia, has also described instances of thought disorder (primarily delusions of control) among his pathognomonic signs for the diagnosis of schizophrenia. Hence, there is widespread agreement that an understanding of thought disorder would greatly increase our understanding of schizophrenia itself.