Cannabis use disorder was the strongest predictor of self-injury in Iraq/Afghanistan veterans, even after controlling for PTSD and depression | Research

The takeaway

A study of Iraq/Afghanistan-era veterans found that cannabis use disorder was significantly associated with both suicidal self-injury (OR 3.10) and nonsuicidal self-injury (OR 5.12) after adjusting for PTSD, depression, alcohol use, traumatic brain injury, and other risk factors.

VA clinicians and veteran mental health providers; suicide prevention researchers; policymakers evaluating cannabis access for veterans.

Cannabis use disorder: OR 5.12 for nonsuicidal self-injury, the strongest predictor across all models

What the researchers found

Researchers examined the association between cannabis use disorder (CUD) and self-injury among Iraq/Afghanistan-era veterans.

After adjusting for sex, age, sexual orientation, combat exposure, traumatic life events, traumatic brain injury, PTSD, depression, alcohol use disorder, and non-cannabis drug use disorder, CUD remained significantly associated with both suicidal self-injury (OR 3.10, p = .045) and nonsuicidal self-injury (OR 5.12, p = .009).

CUD was the only variable significantly associated with self-injury across all three statistical models (combined, suicidal, and nonsuicidal).

The findings are consistent with prior civilian research and suggest CUD may increase veterans' risk for self-injurious behavior.

Why it matters

Veteran suicide prevention is a major public health priority. The finding that cannabis use disorder was more consistently associated with self-injury than PTSD, depression, or alcohol use disorder challenges assumptions about which risk factors deserve the most clinical attention in this population.

The numbers in context

CUD associated with suicidal self-injury: OR 3.10, p = .045. CUD associated with nonsuicidal self-injury: OR 5.12, p = .009. CUD was the only variable significant across all three regression models.

How the study worked

Cross-sectional analysis of Iraq/Afghanistan-era veterans. Self-injury assessed as both suicidal and nonsuicidal. Logistic regression adjusting for multiple established risk factors for self-injury including combat exposure, PTSD, depression, TBI, and substance use disorders.

What this study cannot tell us

Cross-sectional design cannot establish whether CUD causes self-injury or whether both reflect a shared underlying vulnerability. Self-reported measures of cannabis use and self-injury. The study assessed cannabis use disorder, not cannabis use in general, so findings may not apply to controlled cannabis use.

How to read the evidence

Moderate. Well-controlled regression analysis with comprehensive covariate adjustment, but cross-sectional design limits causal inference.

When this study was published

Published in 2018. Debate about cannabis use among veterans with PTSD continues to evolve.

The bigger picture

This complicates the narrative around cannabis as a treatment for veteran PTSD. While some veterans report symptom relief from cannabis, this study suggests that cannabis use disorder specifically is associated with significantly elevated self-injury risk, even after controlling for the conditions cannabis is often used to treat.

Questions still open

Does treating cannabis use disorder reduce self-injury risk in veterans? Is the association driven by CUD itself or by the distress that leads to problematic cannabis use? Would results differ for veterans using medical cannabis under clinical supervision?

Common questions

Does this mean cannabis causes veterans to harm themselves?

Not necessarily. This study found an association between cannabis use disorder and self-injury, but it cannot determine causation. It is possible that veterans who are more distressed or have more complex mental health needs are more likely to both develop CUD and engage in self-injury.

How is cannabis use disorder different from cannabis use?

Cannabis use disorder is a clinical diagnosis involving problematic cannabis use patterns such as inability to cut down, using more than intended, cravings, and continued use despite negative consequences. Many people use cannabis without meeting criteria for the disorder.

Read the original research

The Impact of Cannabis Use Disorder on Suicidal and Nonsuicidal Self-Injury in Iraq/Afghanistan-Era Veterans with and without Mental Health Disorders.

Suicide & life-threatening behavior, 48(2), 140-148

View on PubMed ↗Publisher’s paper ↗

Citation

Kimbrel, Nathan A; Meyer, Eric C; DeBeer, Bryann B; Gulliver, Suzy B; Morissette, Sandra B. (2018). The Impact of Cannabis Use Disorder on Suicidal and Nonsuicidal Self-Injury in Iraq/Afghanistan-Era Veterans with and without Mental Health Disorders.. Suicide & life-threatening behavior, 48(2), 140-148. https://doi.org/10.1111/sltb.12345