Predictability as an index of impaired verbal communication in schizophrenic and affective disorders.

The cloze procedure was used to examine predictability in speech samples from schizophrenic, depressive, manic, schizoaffective and normal subjects. Each speech sample was also rated for particular indices of thought disorder using the Andreasen Scale for the Assessment of Thought, Language and Communication. Schizophrenics were found to be less predictable than other patient groups or normals. Depressives were found to be the most predictable. Correlational analyses of cloze scores and specific thought disorder ratings suggest that reduced predictability is associated with traditional indicators of thought disorder.