GLP-1 Drugs Linked to Lower Substance Abuse and Suicide Risk in Veterans

A large BMJ study examined GLP-1 medication outcomes across 600,000 veterans.

A large-scale observational study published in The BMJ in March 2026 has found that GLP-1 receptor agonists — a class of medications originally developed for type 2 diabetes and obesity — may be associated with a reduced risk of substance use disorders, overdose events, and suicidal ideation among U.S. military veterans. The study, conducted by researchers at Washington University School of Medicine in St. Louis and the VA Saint Louis Health Care System, represents the broadest examination to date of GLP-1 medications and their potential relationship to addiction-related outcomes.

Led by senior author Ziyad Al-Aly, MD, and colleagues including Miao Cai, Taeyoung Choi, and Yan Xie, the research team analyzed electronic health records from more than 600,000 veterans with type 2 diabetes enrolled in the U.S. Department of Veterans Affairs health system. The findings have drawn significant attention from the addiction medicine community, though experts caution that the observational design means the results should be considered hypothesis-generating rather than definitive.

Study Design and Veteran Population

The researchers employed a target trial emulation framework — a method that uses observational data to approximate randomized trial conditions — to compare veterans who initiated GLP-1 receptor agonists against those who began SGLT-2 inhibitors, another class of diabetes medication. SGLT-2 inhibitors served as the active comparator because they share a similar indication but work through a different mechanism that does not involve the brain's reward pathways.

The study population consisted of veterans with type 2 diabetes receiving care through the VA health system. The analysis was divided into two main protocols: one examining whether GLP-1 medications were associated with a lower risk of developing new substance use disorders in veterans without a prior addiction history, and a second evaluating outcomes among veterans who already had a diagnosed substance use disorder at baseline.

According to the researchers, this dual-protocol approach allowed them to assess both the potential preventive and therapeutic dimensions of GLP-1 receptor agonist use in the context of addiction. The veteran population was particularly relevant given the historically elevated rates of substance use disorders and mental health challenges within this group.

Reduced Risk of New Substance Use Disorders

Among veterans with no prior history of addiction, those who initiated GLP-1 receptor agonist therapy showed a lower risk of developing new substance use disorders across all five substance categories studied, compared to those taking SGLT-2 inhibitors. According to the study's findings, the risk reductions included:

• Opioid use disorder: approximately 25% reduction
• Cocaine use disorder: approximately 20% reduction
• Nicotine use disorder: approximately 20% reduction
• Alcohol use disorder: approximately 18% reduction
• Cannabis use disorder: approximately 14% reduction

These associations were observed across a range of commonly prescribed GLP-1 medications, including semaglutide and other agents in the class. The breadth of substances covered — from opioids to nicotine — suggests that the observed associations may involve a common neurobiological mechanism rather than substance-specific effects, according to the research team.

Outcomes for Veterans with Existing Substance Use Disorders

The second arm of the study focused on veterans who already had a diagnosed substance use disorder at the time they initiated GLP-1 therapy. For this group, the results suggested meaningful associations with several clinical outcomes. Compared to those who started SGLT-2 inhibitors, veterans initiating GLP-1 receptor agonists showed:

• Approximately 50% lower risk of substance-related mortality
• Approximately 39% fewer overdose events
• Approximately 31% fewer substance-related emergency department visits
• Approximately 26% fewer substance-related hospital admissions
• Approximately 25% lower risk of suicidal ideation or attempt

The finding regarding suicidal ideation is particularly noteworthy in context. In 2023, the European Medicines Agency conducted a safety review following post-marketing reports that suggested a possible link between GLP-1 drugs and increased suicidal thoughts. Both the EMA and the U.S. Food and Drug Administration subsequently concluded that the available evidence did not support a causal association between these medications and suicidality. A separate large BMJ study published in 2025 similarly found no increased risk. The current study's finding of a potential risk reduction adds a new dimension to this ongoing area of inquiry.

For individuals exploring whether GLP-1 medications may be appropriate for their health goals, resources are available to check if you qualify for treatment programs that include these medications.

Proposed Biological Mechanism and Expert Context

The researchers hypothesize that GLP-1 receptor agonists may influence the brain's mesolimbic dopamine system — a network of neural pathways that plays a central role in reward processing, motivation, and the development of addictive behaviors. GLP-1 receptors are expressed in brain regions involved in reward, including the ventral tegmental area and nucleus accumbens.

According to the research team, by modulating dopamine-driven reward signals, GLP-1 medications may dampen the neurological cravings that drive substance-seeking behavior across multiple substance types. This proposed mechanism is consistent with preclinical studies in animal models that have shown reduced alcohol and drug self-administration following GLP-1 receptor agonist treatment.

However, independent experts have urged caution in interpreting these results. The Science Media Centre noted that the study should be considered "hypothesis generating" and that residual confounding cannot be entirely ruled out. Factors such as health-seeking behavior, motivation to manage chronic conditions, and differences in overall medical engagement between treatment groups may partially explain the observed associations.

The American Hospital Association highlighted the study's significance for veteran health systems, noting that if confirmed by randomized trials, the findings could have implications for integrated treatment approaches that address both metabolic and behavioral health conditions simultaneously.

Both semaglutide and tirzepatide are among the GLP-1 receptor agonists that have garnered attention for potential benefits beyond their approved indications, though neither medication is currently approved for the treatment of substance use disorders.

Limitations and the Path Forward

The researchers and external commentators identified several important limitations. The study population consisted predominantly of older male veterans with type 2 diabetes, which limits the generalizability of the findings to broader populations, including younger adults, women, and individuals without diabetes. Additionally, as an observational study using administrative health records, it cannot establish a causal relationship between GLP-1 use and the observed outcomes.

The research team also acknowledged that residual confounding remains a concern. Veterans who initiate GLP-1 therapy may differ systematically from those who begin SGLT-2 inhibitors in ways that were not fully captured by the available data — including differences in socioeconomic status, treatment adherence, and engagement with mental health services.

Despite these limitations, the scale of the study — encompassing more than 600,000 veterans — and the consistency of the findings across multiple substance categories and clinical endpoints have been described as compelling by several experts in the field. The Brain and Behavior Research Foundation noted that the results align with a growing body of preclinical and epidemiological evidence suggesting that GLP-1 receptor agonists may have clinically meaningful effects on brain reward circuitry.

Multiple randomized clinical trials are now being planned or are underway to test whether GLP-1 receptor agonists can be effectively and safely repurposed for the treatment of substance use disorders. Until those results are available, the current findings remain observational associations that require further validation.

For those interested in learning more about GLP-1 medications and their current approved uses for weight management, view current pricing for available treatment programs.

This article is for informational purposes only and is not medical advice. Consult your healthcare provider before starting any weight loss medication or treatment.