Associations Between Sleep Disturbance and Chronic Pain Intensity and Function: A Test of Direct and Indirect Pathways.

Objectives: Sleep disturbance and chronic pain are related. The present study evaluated both direct and indirect (mediated) pathways through which sleep disturbance might be related to chronic pain intensity and function. Methods: In total, 87 individuals (64% female) with chronic low back pain but not using opioids daily completed questionnaires assessing their sleep disturbance, chronic pain intensity, function, depression, anxiety, positive affect, and catastrophizing. Results: Greater sleep disturbance was associated with greater pain intensity, worse function, greater emotional distress, lower positive affect, and higher levels of catastrophizing. Cross-sectional mediation analyses revealed that the positive associations between sleep disturbance and chronic pain intensity were conveyed statistically not only by significant indirect effects of elevated emotional distress, lower positive affect, and greater catastrophizing associated with sleep disturbance, but also by significant direct effects of sleep disturbance on chronic pain intensity. Similarly, we found that the associations between sleep disturbance and impaired function were conveyed statistically not only by significant indirect effects of elevated chronic pain intensity associated with sleep disturbance, but also by significant direct effects of sleep disturbance on function. Discussion: Sleep disturbance was related significantly with chronic pain intensity and function by both direct and indirect pathways. These results are consistent with an emerging literature highlighting the potential significance of sleep disturbance in chronic pain patients, and provide further support for addressing sleep disturbance in the assessment and management of chronic pain.