Clinical Takeaway
People with PTSD and co-occurring substance use disorders who use cannabis can still benefit meaningfully from trauma-focused treatments, and cannabis use does not appear to undermine treatment outcomes compared to non-users. Clinicians should not withhold or delay evidence-based trauma-focused care for patients on the basis of cannabis use alone.
#5 Cannabis use and trauma-focused treatment for co-occurring posttraumatic stress disorder and substance use disorders: A meta-analysis of individual patient data.
Citation: Hill Melanie L et al.. Cannabis use and trauma-focused treatment for co-occurring posttraumatic stress disorder and substance use disorders: A meta-analysis of individual patient data.. Journal of anxiety disorders. 2024. PMID: 38266511.
Design: 6 Journal: 0 N: 4 Recency: 1 Pop: 2 Human: 1 Risk: -2
This meta-analysis directly addresses a critical clinical gap by examining whether evidence-based trauma-focused treatments maintain efficacy in patients with comorbid PTSD and substance use disorders who are actively using cannabis, a population frequently excluded from or underrepresented in efficacy trials. The findings clarify whether clinicians should modify treatment approaches or patient selection criteria when managing the substantial proportion of trauma-exposed individuals presenting with concurrent cannabis and other substance use. Understanding treatment outcomes across cannabis use status informs real-world clinical decision-making and helps establish whether current PTSD treatment protocols require adaptation for this high-comorbidity population.
Quality Gate Alerts:
- Preclinical only
Abstract: High rates of cannabis use among people with posttraumatic stress disorder (PTSD) have raised questions about the efficacy of evidence-based PTSD treatments for individuals reporting cannabis use, particularly those with co-occurring alcohol or other substance use disorders (SUDs). Using a subset of four randomized clinical trials (RCTs) included in Project Harmony, an individual patient meta-analysis of 36 RCTs (total N = 4046) of treatments for co-occurring PTSD+SUD, we examined differences in trauma-focused (TF) and non-trauma-focused (non-TF) treatment outcomes for individuals who did and did not endorse baseline cannabis use (N = 410; 70% male; 33.2% endorsed cannabis use). Propensity score-weighted mixed effects modeling evaluated main and interactive effects of treatment assignment (TF versus non-TF) and baseline cannabis use (yes/no) on attendance rates and within-treatment changes in PTSD, alcohol, and non-cannabis drug use severity. Results revealed significant improvements across outcomes among participants in all conditions, with larger PTSD symptom reductions but lower attendance among individuals receiving TF versus non-TF treatment in both cannabis groups. Participants achieved similar reductions in alcohol and drug use across all conditions. TF outperformed non-TF treatments regardless of recent cannabis use, underscoring the importance of reducing barriers to accessing TF treatments for individuals reporting cannabis use.
🧠 While this meta-analysis provides valuable real-world data on how cannabis use may moderate trauma-focused treatment outcomes in individuals with co-occurring PTSD and substance use disorders, several important limitations warrant careful interpretation. The analysis draws from a subset of only four RCTs within a larger Project Harmony cohort, which constrains generalizability and statistical power compared to the full dataset, and the abstract does not specify whether cannabis use was measured prospectively, at baseline, or during treatment, introducing potential temporal confounding. Additionally, we lack clarity on cannabis use patterns (frequency, potency, route of administration), concurrent medications, or whether cannabis was being used therapeutically versus problematically, all of which significantly influence clinical outcomes and comparability across studies. That said, this work appropriately addresses a real clinical gap: most evidence-based PTSD treatments were developed and tested in populations with relatively homogeneous substance use profiles, yet many patients in routine practice present with polysubstance involvement including cannabis. Clinicians should interpret any findings cautiously