In 2020, 9.3 million Americans reported prescription opioid misuse and 902,000 reported heroin use (Substance Abuse & Mental Health Services Administration, 2021). Opioid use disorder (OUD) is associated with adverse consequences, including opioid-related overdoses, emergency department visits, and deaths, as well as economic costs estimated at over $78 billion annually (Florence et al., 2016, Geller et al., 2019, Rudd et al., 2016).

Posttraumatic stress disorder (PTSD) is a chronic and debilitating condition that is highly prevalent among individuals with OUD. Nearly 90% of individuals with OUD report lifetime trauma exposure and 33% meet DSM diagnostic criteria for PTSD (Mills et al., 2005, Mills et al., 2006, Peirce et al., 2009). Although medications for opioid use disorder (MOUD; e.g., methadone, buprenorphine) are the most efficacious treatment for OUD (Mattick et al., 2014), MOUD patients with co-occurring PTSD are more likely to drop out of treatment and at greater risk of relapse to opioid use (Peirce et al., 2016, Schiff et al., 2010).

Prolonged exposure (PE) therapy is an empirically supported first-line treatment for PTSD (Jonas et al., 2013, Powers et al., 2010). PE disrupts the cycle of anxiety and avoidance that characterizes PTSD by deconditioning fear responses to trauma-related stimuli via sustained imaginal and in-vivo exposure exercises (Foa et al., 2019). Promising initial examinations of PE among individuals with OUD suggest that PE is safe and associated with significant reductions in PTSD symptoms (Peck et al., 2018, Schacht et al., 2017, Schiff et al., 2015). However, as with other cognitive behavioral interventions for trauma, PE completion rates are often low and present a challenge to PE efficacy, especially among patients with co-occurring PTSD and substance use disorder (SUD; Belleau et al., 2017). A quarter of participants with SUD do not attend a single therapy session (Coffey et al., 2006, Foa et al., 2013, Mills et al., 2012), and up to 62% drop out before completing treatment (Belleau et al., 2017). As a result, fewer than half of patients remain in treatment until the third session when exposure, the active component of treatment, begins (Brady et al., 2001, Mills et al., 2012, Sannibale et al., 2013).

Schacht et al. (2017) evaluated the efficacy of attendance-contingent financial incentives for improving PE attendance among 58 methadone-maintained patients with PTSD. In that study, participants were randomized to receive standard PE alone or PE plus monetary incentives delivered contingent upon attending PE sessions. Participants randomized to the PE + incentives condition attended significantly more therapy sessions and demonstrated greater decreases in PTSD severity compared to those randomized to standard PE. However, because prior studies of PE in individuals with OUD have not included a condition in which patients received MOUD without PTSD-focused therapy, it is unclear to what extent improvements in PTSD symptoms were a function of PE versus the effects of MOUD more generally. This is important as prior studies suggest that MOUD alone, without counseling, is associated with significant improvements in psychiatric symptoms (Streck et al., 2018).

In this 12-week pilot study, we examined the feasibility of PE with financial incentives delivered contingent upon PE session attendance (PE+) for improving therapy attendance and PTSD symptoms among individuals with co-occurring PTSD and OUD as well as the initial efficacy of PE+ compared to standard PE without incentives (PE) and continued MOUD treatment as usual (TAU) without PTSD treatment. We hypothesized that participants randomly assigned to receive PE+ would attend more PE sessions than those randomized to PE and experience greater improvements in PTSD symptoms compared to those randomized to receive either PE or TAU.