Epidemiology of chronic pain with psychological comorbidity: prevalence, risk, course, and prognosis.

OBJECTIVE: To review the relation between chronic pain and psychological comorbidities, and the influence on course and prognosis, based on epidemiologic and population studies.
METHOD: We present a narrative overview of studies dealing with the epidemiology of chronic pain associated with mental health and psychiatric factors. Studies were selected that were of good quality, preferably large studies, and those that dealt with prevalences, course and prognosis of chronic pain, risk factors predicting new pain and comorbid disorders, and factors that affect health outcomes.
RESULTS: Chronic pain is a prevalent condition, and psychological comorbidity is a frequent complication that significantly changes the prognosis and course of chronic pain. In follow-up studies, chronic pain significantly predicts onset of new depressions, and depression significantly predicts onset of new chronic pain and other medical complaints. Age, sex, severity of pain, psychosocial problems, unemployment, and compensation are mediating factors in course and prognosis.
CONCLUSION: In assessment of chronic pain, the evidence from epidemiologic studies makes it clear that chronic pain can best be understood in the context of psychosocial factors.