The form of psychopathology which has probably occasioned the most extensive study of thought and language is schizophrenia. The deviant and sometimes bizarre ways in which such patients use language are among their most striking symptoms, and it has long been orthodox to locate the core of their symptomatic constellation in disorders of cognition. In recent decades, the interest in thought and language has extended beyond the study of the patients themselves to the study of other family members and of the family conceptualized as a system. The examination of forms of thinking and language has subsequently come to be central not just to issues involving diagnosis and the interpretation of symptoms but also to the attempt to understand the etiology of the illness. This tendency is exemplified in the research by Margaret Singer and Lyman Wynne concerning the communication patterns of parents of schizophrenics, probably the most influential and empirically best supported work concerning environmental factors in the etiology of schizophrenia.