Positive and negative symptoms and the thematic organisation of schizophrenic speech.

This study questions the prevailing view that schizophrenic delusions, hallucinations and incoherence of speech (positive symptoms) reflect loss of cognitive control and that flattening of affect and poverty of speech (negative symptoms) reflect restriction of cognitive processing. The prevailing view was examined by analysing the thematic organisation of speech produced by 18 patients describing pictures. Results showed that (a) positive and negative symptom schizophrenics did not differ in the control and restriction of thematic speech organisation; (b) speech disordered schizophrenics, positive as well as negative, showed cognitive restriction, by producing fewer inferential ideas than non-speech disordered schizophrenics. The wider implications of these results are discussed, particularly the implications of (b) for the notion of concreteness in schizophrenia.