Cannabis use following trauma exposure: An observational study of the impact of acute stress and fear response on cannabis outcomes

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PROJECT SUMMARY Exposure to trauma is associated with a range of negative outcomes such as posttraumatic stress disorder (PTSD) and substance use disorder, particularly cannabis. The early posttrauma period (i.e., the days, weeks, and months following exposure) represents a critical period of risk for long term problem behaviors, especially among emerging adults (aged 18-25), which constitutes continued development accompanied by a peak in substance use and increased risk for trauma exposure. As regional laws, cultures, and beliefs about cannabis use (CU) continue to shift, there is concern that trauma exposure may exacerbate use (via self-regulation) and lead to greater cannabis-related problems, as many individuals report using cannabis to relieve distress, hyperarousal, and other posttrauma symptoms. Furthermore, while the majority of US states that have legalized cannabis for medical use include outcomes of stress and trauma, such as PTSD, as qualifying conditions for a state-issued medical marijuana license, little is known about how cannabis may impact the early post-trauma course. Given that the endocannabinoid system plays an essential role in regulating stress response and learned fear, CU in the acute post-trauma period may alter mechanisms contributing to alterations in fear neurocircuitry (e.g., alterations in consolidation/ reconsolidation, retrieval, extinction) and physiological reactivity. Limited (and contradicting) evidence, however, regarding safety and efficacy of cannabis preclude strong conclusions about its potential therapeutic role, with some prospective studies demonstrating detrimental or no long-term effects of CU on PTSD symptoms. The overall goal of our study is to examine the interplay between posttraumatic stress symptoms and cannabis use behavior during the period immediately following trauma exposure. We will recruit and prospectively follow N=200 trauma-exposed regular cannabis users admitted to the general hospital emergency department after medical evaluation for traumatic injury. Upon discharge, participants will complete ecological momentary assessment (EMA) paired with wearable biosensors (smartwatch) to record CU behavior, symptom development, and physiological output (i.e., heart rate) during early trauma recovery. Participants will return for completion of clinical interview and self-report, as well as laboratory procedures to characterize fear extinction and physiological reactivity. The main goals of this research are to: (a) assess alterations in fear response and physiological reactivity associated with CU, (b) characterize the impact of posttraumatic stress symptoms on cannabis use behaviors, and (c) determine whether early markers of altered physiology and posttraumatic stress symptoms are makers for trajectories of long-term adverse cannabis-related outcomes (i.e., use disorder, problems, chronic/heavy use).