Psychiatric comorbidity and co-occurring opioid misuse: Depression mediates the relationship between post-traumatic stress disorder and opioid misuse in community pharmacy settings

Abstract

sBackground: Individuals who misuse opioids frequently have comorbid psychiatric issues, including post-traumatic stress disorder (PTSD) and depression. However, little is known about the mechanisms by which these disorders are associated with opioid misuse and specifically in community pharmacy settings. The current study examined whether depression mediated the relationship between PTSD and opioid misuse in patients filling opioid prescriptions. Methods: We administered a health survey in four community pharmacies among patients filling opioid medications in southwestern Pennsylvania. Univariate statistics were used to assess relationships among demographic and clinical characteristics of PTSD, depression, and opioid misuse behaviors. We then examined whether depression mediated the relationship between PTSD and opioid misuse using ordinary least squares path analysis with bootstrapping. Results: A total of 333 participants completed the health survey. Opioid misuse was reported among 15.9% of all participants, 33.3% among those with a positive PTSD screen, and 29.3% of those who screened positive for depression. Depression significantly mediated the relationship between PTSD and opioid misuse. Specifically, there was a statistically significant indirect effect (ab) of PTSD on opioid misuse through a pathway mediated by depression (ab = .06, SEab = .02, 95% CI = .02–.10). The direct effect (c’) of PTSD on opioid misuse was also significant (c’ = .12, SEc’ = .05, P = .01, 95% CI = .03–.22), suggesting partial mediation. Conclusions: Results suggest an indirect pathway by which clinical intervention may help ameliorate outcomes in patients with PTSD. Further, there is an increased need for screening, assessment, and intervention protocols for this patient population in which community pharmacy is a novel setting to expand future efforts within the patient population.