Objective: To examine the extent to which pain acceptance, pain catastrophising and alexithymia moderate associations between pain intensity and psychological pain medication dependence. Methods: Participants (106 hospital outpatients with chronic spinal pain) completed the Leeds Dependence Questionnaire (LDQ) to measure psychological dependence on pain medication, and the Chronic Pain Acceptance Questionnaire-8 (CPAQ-8), the Pain Catastrophising Scale (PCS) and the Toronto Alexithymia Scale-20 (TAS-20), plus the Depression, Anxiety and Stress Scale-21 (DASS-21). Results: Multiple linear regression showed that degree of psychological dependence (measured dimensionally across the range of LDQ scores) was associated with TAS subscale difficulty identifying feelings (DIF) (β = 0.249, p = <0.002) and PCS subscale rumination (β = 0.193, p = 0.030), independently of pain intensity and risk behaviors for medication misuse. The effect of pain intensity was moderated by rumination, with pain intensity more strongly associated with dependence when rumination was high (interaction β = 0.192, p = 0.004). Logistic regression showed that the effect of pain intensity on severe dependence (measured categorically as LDQ score ≥ 20) was moderated by alexithymia, so that severe dependence was independently associated with the combination of intense pain and high alexithymia (interaction odds ratio = 7.26, 95% CIs = 1.63-32.42, p = 0.009). Conclusions: Rumination and alexithymia moderated the associations between pain intensity and psychological pain medication dependence, consistent with emotion regulation theory. This raises the possibility that specifically targeting rumination about pain and symptoms of alexithymia could potentially improve the effectiveness of psychological interventions for chronic pain and help people to avoid or reduce their psychological dependence on pain medication.
Keywords: Alexithymia; chronic spinal pain; pain catastrophising; pain medication dependence; rumination.