Psychosocial measures in musculoskeletal trials

Measurement of psychological and social factors in studies of musculoskeletal disorders has become increasingly important with the need to show an effect of interventions on individuals' lives. Because information of psychological states involves patients reporting their private sensations, specific issues of their assessment need to be considered. Two of these issues are the problem of what constitutes the gold standard and the interpretation of causal direction of effects. The role of psychosocial factors in the assessment of disability is often ignored and frequently the distinction between disability and handicap confused. I describe and discuss the different measures commonly used to assess disability in arthritis. The assessment of symptoms, such as pain, stiffness, and fatigue are considered, as well as the examination of psychological well being. Interactions between these factors are also discussed. A number of other psychological variables have been developed and found to play a mediating role between the illness and its effect. These include coping, social support and other health cognitions, such as perceptions of control. The important role of psychosocial factors and their effect on measures on symptoms and disability suggest that need for more detailed examination of factors associated with outcome, and also the need to consider more complex designs that control for some of these factors at the outset of studies.