Speech performance in mania and schizophrenia: the association of positive and negative thought disorders and...

The speech performance of manics (n = 21) and schizophrenics (n = 22) was assessed with both clinical evaluations and an assessment of reference performance. The severity of positive and negative clinical thought disorders was correlated with the frequency of incompetent (unclear and ambiguous) references as measured with a linguistic rating system. It was found that pressure of speech accounted for the majority of the variance in incompetent references in the manic sample, while this relationship was not found for the schizophrenics. The number of incompetent references in the schizophrenic sample was most highly predicted by the severity of derailment, with poverty of content of speech the next most important. These results were discussed with respect to their implications for the identification of differential mechanisms underlying speech disorders in the two patient groups.