A number of clinical observations indicate that
pain processing might be disturbed in
psychotic disorders such as
schizophrenia. Only a few studies have investigated pain perception in
schizophrenia. The main objective of this study was the investigation of thresholds of warmth perception (WP), thermal
pain onset (TPO) and thermal
pain tolerance (
TPT) in acute schizophrenic patients and the influence of
antipsychotic medication on the patients' responses. We investigated 23 schizophrenic subjects who had been not received
antipsychotic treatment for 8 weeks, and we then reassessed them 3 days later after the introduction of
neuroleptics. Acute symptoms of
schizophrenia were measured using the Scales for the Assessment of Positive and Negative Symptoms. Thresholds were determined by a contact thermode on both volar wrists. Schizophrenic patients showed significantly increased thresholds of WP and TPO relative to healthy controls.
Antipsychotics did not alter pain thresholds. We found no correlation between pain perception and psychometric scales. Our findings demonstrate altered warmth and heat pain perception in acute
schizophrenia. We believe that our findings can be attributed to information-processing abnormalities of the disorder and that they are not specific to
pain processing, per se, since both WP and TPO were significantly different. Future studies should evaluate attentional deficits in
schizophrenia in relation to pain perception.