The association between chronic widespread pain and mental disorder - A population-based study

Objective. Patients with chronic widespread pain (CWP) have been reported t o have a greater prevalence of mental disorders and somatization than that found in the general population, but the true association between CWP and m ental disorders is unknown. In this study, we investigated whether there is an increased prevalence of mental disorder in people with CWP from the gen eral population. We also describe the psychiatric diagnoses associated with CWP, Methods, In a population-based case-control study, 1,953 subjects (75% of a random sample of individuals age 18-65 years) completed a questionnaire th at included a pain assessment and the 12-item General Health Questionnaire (GHQ-12), Of 710 subjects scoring >1 on the GHQ-12, 301 were assessed furth er using a structured psychiatric interview and detailed assessment of medi cal records to identify cases of mental disorder, in accordance with criter ia of the 10th edition of the International Classification of Diseases. The association between CWP and mental disorder was modeled using logistic reg ression, adjusting for possible confounders including age, sex, and nonresp onders, Results. We estimated the overall population prevalence of mental illness t o be 11.9%, The odds of having a mental disorder for subjects with versus t hose without CWP were 3.18 (95% confidence interval 1.97-5.11), Most subjec ts with mental disorders were diagnosed as having mood and anxiety disorder s. Only 3 cases of somatoform disorders were identified, and all were assoc iated with pain. Conclusion. This study, although unable to demonstrate a cause-and-effect r elationship, showed that 16.9% of those with CWP were estimated to have a p sychiatric diagnosis, suggesting that these disorders should be identified and treated.