Quality of thought disorder in differential diagnosis.

The authors used a reliable scale to assess quantity and quality of thought disorder in manic, schizophrenic, schizoaffective manic, and schizoaffective depressed patients. High levels of thought disorder occurred in all psychotic groups except in the schizoaffective depressed group. Manic patients produced thought disorders that revealed both prominent combinatory thinking and intrusions of irrelevant ideas into the stream of discourse, usually with flippancy and humor. The thinking of schizophrenic patients was confused and fluid, and usually peppered with many idiosyncratic and peculiar words and phrases. Although schizoaffective manic patients resembled manics in their tendency to show combinatory thinking, their productions lacked the jocularity of the manics. The schizoaffective manic patients more strongly resembled the schizophrenic patients in their production of idiosyncratic verbalizations and in confused thinking. Schizoaffective depressed patients showed a strikingly constricted output, but produced a few noteworthy absurd responses, and in that respect resembled the schizophrenic patients. The authors suggest that quality of thought disorder differs in schizophrenia and in mania, and that the thought disorder of schizoaffective conditions resembles that of schizophrenia.