Trauma patients who tested positive for THC were 66% more likely to screen positive for post-traumatic stress symptoms | Research

The takeaway

Among nearly 2,000 trauma patients at a Level 1 center, those who tested positive for THC on admission were significantly more likely to screen positive for post-traumatic stress symptoms, even after adjusting for injury severity and other factors.

Trauma surgeons, emergency psychiatrists, PTSD researchers, harm reduction advocates

OR 1.66 for positive PTSD screening among THC-positive trauma patients

What the researchers found

THC-positive patients were more likely to screen positive on the Posttraumatic Adjustment Scale (19.6% vs. 13.2%, p = 0.001). After adjusting for age, sex, injury severity, assault mechanism, polysubstance use, ICU admission, and complications, THC use remained independently associated with a positive PAS screen (OR 1.66, 95% CI 1.23-2.24).

Why it matters

This raises questions about whether pre-existing cannabis use is a marker for psychological vulnerability to trauma. If THC users are at higher risk for post-traumatic distress, they may benefit from enhanced mental health screening after traumatic injuries.

The numbers in context

1,960 patients; 437 (22.3%) screened PAS-positive. THC positive in 19.6% of PAS-positive vs. 13.2% of PAS-negative patients (p = 0.001). Adjusted OR = 1.66 (95% CI 1.23-2.24, p = 0.001). Male sex was protective; younger age and assault-related injury increased risk.

How the study worked

Retrospective cohort study at a Level 1 trauma center (January 2023 to December 2024). 1,960 adult trauma patients who completed inpatient PAS screening were included. THC use was identified via admission urine drug screen. Multivariable logistic regression adjusted for demographic and clinical confounders.

What this study cannot tell us

Retrospective design cannot establish causation. Urine drug screen detects recent use, not use at time of trauma. No information on frequency, dose, or reason for cannabis use. PAS is a screening tool, not a PTSD diagnosis. Single center.

How to read the evidence

Large single-center retrospective cohort with appropriate multivariable adjustment, but observational design and reliance on urine drug screening limit causal inference.

When this study was published

2026 publication using 2023-2024 data

The bigger picture

Cannabis is often discussed as a potential treatment for PTSD, but this study suggests that pre-trauma cannabis use may actually signal heightened vulnerability. The direction of the relationship matters: is cannabis a risk factor, a marker for pre-existing vulnerability, or both?

Questions still open

Does cannabis use before trauma increase PTSD risk, or do people prone to PTSD also tend to use cannabis? Would prospective studies with detailed cannabis use histories clarify the direction of this association?

Common questions

Does this mean cannabis causes PTSD?

No. The study found an association between recent THC use and post-traumatic stress screening results but cannot determine whether cannabis use contributed to the vulnerability or was coincidental.

What is the Posttraumatic Adjustment Scale?

A screening tool administered to trauma patients in the hospital to identify those at risk for developing PTSD, measuring early signs of psychological distress after injury.

Read the original research

Pre-Trauma THC Use Is Associated With a Positive Posttraumatic Adjustment Scale Screening.

The American surgeon, 92(3), 740-745

View on PubMed ↗Publisher’s paper ↗

Citation

Miller, Jeremy; Alvarez, Claudia; Berki, Lauren; Linsley, Catherine; Woods, John; Strumwasser, Aaron; Vanderet, Danielle; Jebbia, Mallory. (2026). Pre-Trauma THC Use Is Associated With a Positive Posttraumatic Adjustment Scale Screening.. The American surgeon, 92(3), 740-745. https://doi.org/10.1177/00031348251381622