The moderating role of fatigue sensitivity in the relation between depression and alcohol and opioid misuse among adults with chronic low back pain

Objective: Chronic low back pain is the second leading cause of disability in the United States and is frequently related to increased risk of opioid and alcohol misuse. Depression is associated with poor substance use outcomes among persons with chronic low back pain. Theoretically, the influence of depression on opioid and alcohol misuse among those with chronic low back pain may vary as a function of fatigue sensitivity. Method: To empirically test this theorized model, the current study examined fatigue sensitivity as a moderator for the relation between depression and opioid and alcohol misuse among 291 adults (69.1% female, M_age = 45.77 years, SD = 11.22) with chronic low back pain currently using opioids. Results: Results suggested that fatigue sensitivity moderated the effect of depression on opioid misuse (β = 0.60, p =.001, 95%CI [0.02, 0.06]) and alcohol misuse (β = 0.45, p =.025, 95%CI [0.002, 0.03]). Examination of simple slopes revealed that the association between depression and opioid and alcohol misuse was statistically significant for those with higher levels of fatigue sensitivity, but not lower levels of fatigue sensitivity. Conclusions: Overall, the current investigation provides initial empirical support for the moderating role of fatigue sensitivity in the relation between depression and alcohol and opioid misuse among adults with chronic low back pain.