The direct and indirect effects of the negative affectivity trait on self reported physical function among patients with upper extremity conditions

Negative affectivity is a personality trait that predisposes people to psychological distress and low life satisfaction. Negative affectivity may also affect pain intensity and physical function in patients with musculoskeletal conditions. We explored the association of negative affectivity to pain intensity and self-reported physical function, and tested whether pain intensity mediates the effect of negative affectivity on physical function. In a cross-sectional study, 102 patients with upper extremity musculoskeletal conditions presenting to an orthopedic surgeon completed self-report measures of negative affectivity, pain intensity, and physical function in addition to demographic and injury information. We used the Preacher and Hayes' bootstrapping approach to quantify the indirect effect of negative affectivity on physical function through pain intensity. Negative affectivity correlated with greater pain intensity and lower self-reported physical function significantly. Also, pain intensity mediated the association of negative affectivity with physical function. The indirect effect accounted for one-third of the total effect. To conclude, negative affectivity is associated with decreased engagement in daily life activities both directly, but also indirectly through increased pain intensity. Treatments targeting negative affectivity may be more economical and efficient for alleviation of pain and limitations associated with musculoskeletal illness than those addressing coping strategies or psychological distress.