Public Health

OBJECTIVE To determine whether exogenously reduced psychological distress reduces reported low-back pain (LBP) and is associated with reduced medical visits for LBP. DATA SOURCES National Health Interview Survey, National Ambulatory Medical Care Survey, National Hospital Ambulatory Medical Care Survey, 1998-2004. STUDY DESIGN We estimate a fuzzy regression discontinuity model in which a discontinuity in the prevalence of psychological distress is identified by exogenous national events. We examine whether this discontinuity induced a corresponding discontinuity in the prevalence of LBP. We additionally estimate a regression discontinuity model to determine associated changes in medical visits with LBP as the primary complaint. PRINCIPAL FINDINGS The prevalence of LBP was discontinuously reduced by one-fifth due to the exogenous national discontinuous reduction in psychological distress. This discontinuity in LBP cannot be explained by discontinuities in employment, insurance, injuries/poisoning, general health status, or other factors. We find an associated three-fifth discontinuous reduction in medical visits with LBP as the primary complaint. CONCLUSIONS On a monthly basis, 2.1 million (P < .01) adults ceased to suffer LBP due to the national reduction in psychological distress, and associated medical visits with LBP as the primary complaint declined by 685 000 (P < .01).