Pain sensitivity in patients with schizophrenia: a systematic review and meta-analysis

Abstract

Background. Alterations in pain perception have been observed in people diagnosed with schizophrenia. Some research suggests the existence of a possible hyposensitivity, while others describe a hypersensitivity to pain in people with schizophrenia. In summary, the studies present contradictory results.

Methods. A systematic review of experimental and comparative studies has been conducted in 5 different databases, including those studies that measure pain experimentally inducing it with physical methods and that compares the results with a healthy control group. Afterwards, a meta-analysis was carried out comparing the patients with schizophrenia to the healthy controls, using
the random effects model.

Results. Nine studies were finally selected, with a total of 186 participants diagnosed with schizophrenia and 186 healthy controls. In the meta-analysis, no significative differences were observed in the general analysis. But when the type of stimuli was studied separately (mechanical, thermal, or electrical), significative differences in favor of a higher sensitivity in the patients with schizophrenia were observed in the studies that measured pain with mechanical pressure or ischemia, not in those that used thermal or electrical methods.

Conclusions. The global result of our systematic review does not support the existence of an alteration in pain sensitivity in subjects with schizophrenia, although a subgroup analysis suggests that when pain stimulation is caused by mechanical methods, people with schizophrenia present hypersensitivity to pain compared to healthy controls. Although these results are novel data, more studies are required to replicate these results.