Cannabis Use Worsened PTSD Symptoms in Veterans, and PTSD Predicted Cannabis Disorder

In a longitudinal study of 361 veterans, cannabis use predicted worsening trauma intrusion symptoms over 6 months, while PTSD diagnosis predicted the development of cannabis use disorder over 12 months.

Metrik, Jane et al.·Psychological medicine·2022·Strong EvidenceLongitudinal Cohort
RTHC-04061Longitudinal CohortStrong Evidence2022RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Longitudinal Cohort
Evidence
Strong Evidence
Sample
N=11

What This Study Found

Using cross-lagged panel modeling, baseline cannabis use significantly predicted worse intrusion symptoms at 6 months (beta=0.46). The reverse association (intrusions predicting use) was weaker (beta=0.22). PTSD diagnosis at baseline predicted cannabis use disorder at 12 months (beta=0.15), but CUD did not significantly predict PTSD.

Key Numbers

361 veterans; 3 timepoints (baseline, 6mo, 12mo); cannabis to intrusions beta=0.46; intrusions to cannabis beta=0.22; PTSD to CUD beta=0.15

How They Did This

Prospective longitudinal study of 361 post-9/11 veterans with assessments at baseline, 6 months, and 12 months using random intercept cross-lagged panel models to distinguish within-person changes from between-person differences.

Why This Research Matters

Many veterans use cannabis to self-medicate PTSD, but this study suggests cannabis may actually worsen the core intrusive symptoms of PTSD over time, creating a self-reinforcing cycle.

The Bigger Picture

The bidirectional relationship between cannabis use and PTSD has significant implications for veteran health policy. If cannabis worsens PTSD while PTSD drives cannabis use, both conditions may escalate together.

What This Study Doesn't Tell Us

Observational study, though the cross-lagged design provides stronger causal inference than cross-sectional data. Sample limited to post-9/11 veterans.

Questions This Raises

  • ?Would CBD-dominant products have a different effect on PTSD intrusion symptoms than THC-dominant cannabis?
  • ?Could targeted interventions break the cannabis-PTSD cycle?

Trust & Context

Key Stat:
Cannabis predicted worsening intrusions (beta=0.46)
Evidence Grade:
Prospective longitudinal design with cross-lagged panel modeling provides stronger causal inference than most observational studies.
Study Age:
Published in 2022
Original Title:
Cannabis use and posttraumatic stress disorder: prospective evidence from a longitudinal study of veterans.
Published In:
Psychological medicine, 52(3), 446-456 (2022)
Database ID:
RTHC-04061

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Follows a group of people over time to track how outcomes develop.

What do these levels mean? →

Frequently Asked Questions

Does cannabis help or worsen PTSD?

This study found cannabis use predicted worsening of trauma intrusion symptoms at 6 months (beta=0.46), suggesting that despite subjective relief, cannabis may actually make core PTSD symptoms worse over time.

Is there a cycle between PTSD and cannabis use?

Yes. The study found a bidirectional relationship: cannabis worsened intrusive PTSD symptoms, while PTSD predicted development of cannabis use disorder, suggesting a self-reinforcing cycle.

Read More on RethinkTHC

Cite This Study

RTHC-04061·https://rethinkthc.com/research/RTHC-04061

APA

Metrik, Jane; Stevens, Angela K; Gunn, Rachel L; Borsari, Brian; Jackson, Kristina M. (2022). Cannabis use and posttraumatic stress disorder: prospective evidence from a longitudinal study of veterans.. Psychological medicine, 52(3), 446-456. https://doi.org/10.1017/S003329172000197X

MLA

Metrik, Jane, et al. "Cannabis use and posttraumatic stress disorder: prospective evidence from a longitudinal study of veterans.." Psychological medicine, 2022. https://doi.org/10.1017/S003329172000197X

RethinkTHC

RethinkTHC Research Database. "Cannabis use and posttraumatic stress disorder: prospective ..." RTHC-04061. Retrieved from https://rethinkthc.com/research/metrik-2022-cannabis-use-and-posttraumatic

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.