Among patients with opioid use disorder (OUD), 90% report lifetime trauma exposure and 33% meet criteria for posttraumatic stress disorder (PTSD). The co-occurrence of OUD and PTSD is associated with more severe mental health symptoms and worse opioid agonist treatment (OAT) outcomes relative to either diagnosis alone. Prolonged exposure therapy (PET) is an efficacious manualized cognitive-behavioral treatment for reducing PTSD severity. Although preliminary findings indicate that PET may reduce PTSD symptom severity among patients receiving treatment for concomitant OUD, it is unclear to what extent observed improvements were a function of PET versus the psychopharmacological effects of OAT itself. Therefore, the question of whether OAT alone may attenuate PTSD symptomatology in the absence of intensive cognitive-behavioral therapy remains unanswered and is important given the prevalence and deleterious effects of PTSD among OAT patients, as well as the ever-present constraints on mental health resources in substance use treatment settings.

The present study will investigate the contribution of PET above and beyond OAT alone for reducing PTSD symptomatology among adults with concurrent PTSD and OUD. Eligible participants who complete the informed consent process will be randomized to one of three conditions: (a) OAT as usual, (b) OAT + PET, or (c) OAT + Enhanced PET (OAT+PET+). Those randomized to OAT as usual will continue to receive standard buprenorphine or methadone treatment from their current treatment provider and complete assessments of PTSD symptom severity, psychosocial functioning and drug use at intake and Study Weeks 4, 8, and 12. Follow-up assessment visits will be conducted in-person at our clinic following all relevant COVID-19-related CDC guidelines and university safety protocols. However, study measures may also be administered remotely via phone or telemedicine to reduce the risk of COVID-19 transmission. In addition to receiving OAT and completing monthly assessments, OAT+PET participants will receive PET consisting of 12 weekly, individual sessions with a trained therapist. Therapy sessions will be conducted at our research clinic or remotely via telemedicine to reduce the risk of COVID-19 transmission. Finally, OAT+PET+ participants will receive the procedures noted above for the OAT+PET group plus monetary incentives delivered contingent upon completion of PET sessions. Given the poor PET adherence rates reported among patients with substance use disorder (SUDs), the use of incentives will ensure that we evaluate PET effects among patients who receive a sufficient dose of therapy.

For inclusion in the study, participants must meet the following criteria: (a) \> 18 years of age, (b) currently maintained on a stable methadone or buprenorphine dose for the treatment of OUD for \>1 month prior to the study, (c) endorse \>1 lifetime traumatic event, and (c) meet the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) PTSD diagnostic criteria (American Psychiatric Association, 2013). Exclusion criteria include: (a) the presence of an acute psychotic disorder, bipolar disorder with an active manic episode (but not simply the presence of bipolar disorder), (b) imminent risk for suicide, (c) a medical condition that may interfere with consent or participation (e.g., organic brain syndrome, dementia, head injury, neuropathy, etc.), and (d) illiteracy in English.

Participants randomized to OAT as usual will continue to receive standard buprenorphine or methadone maintenance from their current treatment provider and complete assessments of PTSD symptom severity, psychosocial functioning and drug use at Study Weeks 4, 8, and 12. Follow-up assessment visits will be conducted in-person at our clinic following all relevant COVID-19-related CDC guidelines and university safety protocols. However, study measures may also be administered remotely via phone or telemedicine to reduce the risk of COVID-19 transmission. In addition to receiving standard buprenorphine- or methadone-maintenance treatment as described above and completing monthly assessments, OAT+PET participants will also receive 12 individual sessions of PET. Therapy sessions will be conducted at our research clinic or remotely via telemedicine to reduce the risk of COVID-19 transmission. Beginning in Study Week 1, OAT+PET participants will complete weekly 60-minute PET sessions provided by a therapist trained in PET. Participants randomized to the OAT+PET+ condition will receive the procedures noted above for the OAT+PET group plus monetary incentives delivered contingent upon completion of PET sessions. Each consecutive attended session will increase the voucher amount so that each consecutively attended appointment is worth an incrementally higher dollar amount. To support completion of the full 12-week PET protocol, we will also incorporate additional strategically-placed bonuses into the reinforcement schedule with the goal of maximizing the percentage of subjects who complete the full 12-session protocol. First, to support consistent (vs. sporadic) attendance, participants will receive a bonus for every two consecutive sessions attended. Second, to support completion of the full PET protocol, participants will receive an additional bonus upon completion of Session 12.