Pragmatic language skills were examined in schizophrenia patients compared to IQ-matched control subjects measured by the decoding of the flouting of the four Gricean maxims.

19 schizophrenic patients and 19 matched controls were evaluated. Five experimental conditions (all included four stories) were used, such as „quantity maxim” (QNM) condition, „quality maxim” (QLM) condition, „relevance maxim” (RM) condition, „manner maxim” (MM) condition and "control” (C) condition. An investigator presented the stories and asked for the hidden communicative intentions. PANSS scores and general intelligence were also measured.

Patients with schizophrenia performed significantly worse than controls in each of the conditions containig the flouting of the Gricean maxims. The response accuracy in the C condition was not differed significantly between the two groups (QNM:p< 0.001; QLM:p< 0.001; RM:p< 0.001; MM:p< 0.001; C:p=0.487). Significant positive correlations were found between QLM and IQ (p< 0.001) and between RM and IQ (p=0.025), and there was no significant correlatios between PANSS scores and response accuracy. Full scale IQ was not differed significantly between the two groups (p=0.095).

We found that a complex pragmatic language deficit exists in schizophrenia. The impairment do not seem to have a relationship with symptom severity. Besides, it seems, that good intellectual function supports pragmatic language skills in schizophrenia.