THE CATEGORIZATION OF THOUGHT-DISORDER

We describe the development of a new system for categorizing thought d isorder. In the development phase (Study 1), we examined the degree to which speech samples and definitions of thought disorder subtypes tak en from: (1) the Scale for the Assessment of Thought, Language, and Co mmunication (TLC); (2) the Thought Disorder Index (TDI); and (3) the A ssessment of Bizarre-Idiosyncratic Thinking (BIT), reflected disturban ces in form versus disturbances in content. Ratings were provided by n aive judges, experienced clinicians, and linguistic experts. The resul ts contributed to the development of a new system dividing thought dis order into disturbances in (1) fluency, (2) discourse coherence, (3) c ontent, and (4) social convention. In the validation phase (Study 2), 21 schizophrenic and 19 manic subjects were interviewed, interpreted p roverbs, and responded to Rorschach cards. Subjects' speech was rated using the TLC, TDI, and BIT. We also measured hallucinations, delusion s and digit span performance. The results of Study 2 provided evidence supporting the validity of our new categorization system.