If investigators wish to use a screening instrument as a case detector, the shorter GHQ is remarkably robust and works as well as the longer instrument. The latter should only be preferred if there is an interest in the scaled scores provided in addition to the total score.

Context.-There is little information on the extent of persistent pain across cultures. Even though pain is a common reason for seeking health care, information on the frequency and impacts of persistent pain among primary care patients is inadequate.Objective.-To assess the prevalence and impact of persistent pain among primary care patients.Design and Setting.-Survey data were collected from representative samples of primary care patients as part of the World Health Organization Collaborative Study of Psychological Problems in General Health Care, conducted in 15 centers in Asia, Africa, Europe, and the Americas.Participants.-Consecutive primary care attendees between the age of majority (typically 18 years) and 65 years were screened (n = 25 916) and stratified random samples interviewed (n = 5438).Main Outcome Measures.-Persistent pain, defined as pain present most of the time for a period of 6 months or more during the prior year, and psychological illness were assessed by the Composite International Diagnostic Interview. Disability was assessed by the Groningen Social Disability Schedule and by activitylimitation days in the prior month.Results.-Across all 15 centers, 22% of primary care patients reported persistent pain, but there was wide variation in prevalence rates across centers (range, 5.5%-33.0%). Relative to patients without persistent pain, pain sufferers were more likely to have an anxiety or depressive disorder (adjusted odds ratio [OR], 4.14; 95% confidence interval [CI], 3.52-4.86), to experience significant activity limitations (adjusted OR, 1.63; 95% CI, 1.41-1.89), and to have unfavorable health perceptions (adjusted OR, 1.26; 95% CI, 1.07-1.49). The relationship between psychological disorder and persistent pain was observed in every center, while the relationship between disability and persistent pain was inconsistent across centers.Conclusions.-Persistent pain was a commonly reported health problem among primary care patients and was consistently associated with psychological illness across centers. Large variation in frequency and the inconsistent relationship between persistent pain and disability across centers suggests caution in drawing conclusions about the role of culture in shaping responses to persistent pain when comparisons are based on patient samples drawn from a limited number of health care settings in each culture. JAMA. 1998;280:147-151 PAIN is one of the most common 1 and among the most personally compelling reasons for seeking medical attention.People seek health care for pain not only for diagnostic evaluation and symptom relief, but also because pain interferes with daily activities, causes worry and emotional distress, and undermines confidence in one's health. When pain persists for weeks or months, its broader effects on well-being can be profound. Psychological health and performance of social responsibilities in work and family life can be significantly impaired. 2Despite evidence that pain affects well-being, little is known about how common persistent pain i...