Abstract
Manic (
n
= 22) and schizophrenic (
n
= 28)
patients were examined with clinical and linguistic measures of language
performance at an acute admission and at a follow-up. It was found that the
frequency of incompetent references and the severity of negative thought
disorder were stable independent traits of schizophrenics. Furthermore, low
levels of verbal productivity, indexed both clinically and linguistically,
predicted the likelihood that schizophrenic subjects would be psychotic at
follow-up. The language performance of manic patients was not temporally stable,
although high levels of reference failures at index predicted psychosis at
follow-up. These results are evaluated in terms of their implications for
differentiating state-specific aspects of speech competence from potential
vulnerability markers in these two types of patients.
