The prevalence and moderators of clinical pain in people with schizophrenia: a systematic review and large scale meta-analysis.

BACKGROUND People with schizophrenia frequently have physical comorbidities that can cause pain. Experimental studies report reduced pain sensitivity among schizophrenia patients, but it remains unclear if clinically relevant pain is less prevalent in schizophrenia. METHOD We systematically searched major electronic databases from inception till 03/2014. Articles were included that reported the prevalence of clinical pain in people with schizophrenia. Two independent authors conducted searches, completed methodological quality assessment and extracted data. A random effects relative risks (RR) meta-analysis was conducted to determine the prevalence of all-cause and specific pain in schizophrenia, and the relative prevalence compared to the general population, and to assess moderators. RESULTS Altogether, 14 studies were included encompassing 242,703 individuals with schizophrenia (30.2-55.8 years) and 4,259,221 controls. Different types of pain were considered. The overall pooled prevalence of clinical pain in people with schizophrenia was 34.7% (95% CI=23.6-46.6). In the comparative analysis involving 7 studies with controls, the RR was 0.99 (95% CI=0.83-1.19). The pooled prevalence of headache among 94,043 individuals with schizophrenia was 29.9% (95% CI=3-69%) and the RR compared to 4,248,284 controls was 1.32 (95% CI=0.85-2.07). In moderator analyses, neither age, sex, study quality or pain assessment method influenced pain prevalence. CONCLUSION Clinical pain affects a third of people with schizophrenia and levels are similar with age- and sex-comparable controls. Future research is needed to determine if similar clinical pain prevalences in schizophrenia occur despite having more painful conditions, resulting from under-reporting, higher pain thresholds or lower help seeking behaviours.