Background: Sleep disturbance is a common complaint of patients with cancer and is well established in both pain conditions and post-traumatic stress disorder (PTSD). An estimated one-third of patients with cancer develop symptoms of PTSD at some point in their treatment. However, few studies have evaluated the contributions of PTSD and sleep disturbance to pain processes in cancer populations. The current study used mediation models to test the hypothesis that sleep disturbance would mediate the relationships between PTSD symptoms and pain intensity and PTSD symptoms and pain interference in a sample of patients with cancer.
Methods: A cross-sectional, retrospective chart review was conducted of the electronic medical records of 85 adult patients with cancer (89.4% female; 59% white; 42% metastatic) who sought individual psychosocial support services at our institution.
Results: Post-traumatic stress disorder symptoms, sleep disturbance, pain intensity, and pain interference were all positively correlated ( P < .01). Clinical levels of PTSD symptoms were reported by 30% to 60% of the sample. Even after controlling for metastatic disease, race, and cancer type, sleep disturbance mediated the relationships between PTSD symptoms and pain intensity ( B = 0.27; 95% CI: 0.10-0.44) and PTSD symptoms and pain-related interference ( B = 0.58; 95% CI: 0.28-0.87).
Conclusions: The relationships among PTSD symptoms, pain intensity, and pain interference could be explained by co-occurring sleep disturbance. Given the high frequency of PTSD symptoms among patients with cancer and PTSD's known links to sleep problems and pain, clinicians should be attentive to the role that traumatogenic processes may play in eliciting sleep and pain-related complaints among patients with cancer.
Keywords: PTSD; cancer; mediation; pain intensity; pain interference; sleep disturbance.