A cross-national study of the course of persistent pain in primary care.

Data from the World Health Organization's study of psychological problems in general health care were used to examine the course of persistent pain syndromes among primary care patients. Across 15 sites in 14 countries, 3197 randomly selected primary care patients completed baseline and 12-month follow-up assessments of pain, other somatic symptoms, and anxiety and depressive disorders (the Composite International Diagnostic Interview), and an assessment of occupational role disability (the Social Disability Schedule). Of patients with a persistent pain condition at baseline, 49% had not recovered 12 months later. The probability of non-recovery varied significantly across study centers and was significantly associated with the number of pain sites at baseline. After adjustment for age, sex, and study center, baseline anxiety or depressive disorder did not predict non-recovery of persistent pain. Among those without a persistent pain disorder at baseline, the rate of onset was 8.8% with a significant variability in risk across centers. The baseline characteristics predicting the onset of persistent pain disorder were psychological disorder, poor self-rated health, and occupational role disability. A persistent pain disorder at baseline predicted the onset of a psychological disorder to the same degree that a baseline psychological disorder predicted the subsequent onset of persistent pain. Persistent pain conditions are common among primary care patients, and the probability of resolution over 12 months is approximately 50%. We found a strong and symmetrical relationship between persistent pain and psychological disorder. Impairment of daily activities appears to be a central component of that relationship.