Heightened healthcare utilization & risk of mental disorders among Veterans with comorbid opioid use disorder & posttraumatic stress disorder

•Comorbid OUD and PTSD heightens risk of emergency room and inpatient care.•Veterans with this comorbidity are more likely to have MDD and somatoform disorder.•Comorbid OUD and PTSD also increases risk of functional impairment and suicidality. Although Veterans with posttraumatic stress disorder (PTSD) are vulnerable to opioid misuse, there is limited research evaluating the psychosocial and medical sequalae experienced by Veterans with comorbid PTSD and opioid use disorder (OUD). Using data from a nationwide, longitudinal registry of Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND) Veterans oversampled for PTSD with a 1:1 ratio of men to women, we identified Veterans with lifetime diagnoses of comorbid PTSD and OUD (n = 40), PTSD and non-opioid substance use disorder (SUD; n = 386), PTSD only (n = 901), and non-opioid SUD only (n = 52) using medical record data. We then compared these groups on Veterans Affairs emergency, urgent care, and inpatient healthcare utilization, suicide risk, functional impairment, and the presence of comorbid mental conditions in the following 1–2 years. Relative to all other groups, Veterans with comorbid OUD and PTSD had increased likelihood of emergency room and inpatient care, probable somatoform and major depressive disorders, and greater functional impairment. Both the PTSD/OUD group and PTSD/non-opioid SUD group demonstrated increased suicidality, urgent care utilization, and probable generalized anxiety disorder relative to Veterans with PTSD only or non-opioid SUD only. Results suggest that comorbid OUD and PTSD are associated with greater likelihood of negative psychiatric and healthcare related outcomes, even relative to PTSD comorbid with other types of SUDs. Findings support the importance of concentrated and sustained efforts to improve prevention and intervention strategies for Veterans struggling with PTSD symptoms and opioid misuse.