Expert Commentary

Opioid crisis in U.S. military driven by combat exposure in the war on terror, research finds

Research for the first time shows a causal link between combat exposure and prescription painkiller misuse.

(Israel Palacio / Unsplash)

United States military service members who experience combat are more likely to misuse prescription painkillers than those who don’t engage in combat, according to a new working paper from the National Bureau of Economic Research.

Prescription painkiller misuse is 7 percentage points higher among service members whose units were deployed to combat zones and engaged with enemy fighters, compared with those deployed to combat zones whose units didn’t engage the enemy, the authors find.

“This study is the first to estimate the causal impact of combat deployments in the Global War on Terrorism on opioid abuse,” the authors write.

They also find that younger, enlisted personnel are at greater risk for misusing prescription painkillers after combat exposure. Service members in the authors’ sample come from similar socioeconomic backgrounds. This suggests the association is driven by what happens on the battlefield, not other factors like race, ethnicity and income levels that have been broadly linked to opioid misuse.

“Among military populations, combat is a very major reason for the opioid epidemic,” says Resul Cesur, an associate professor of healthcare economics at the University of Connecticut and one of the paper’s authors. “It’s not because of who these people are. It’s because of what they are being exposed to.”

The authors conservatively estimate that government health care costs top $1 billion per year to treat active-duty service members and veterans who misuse prescription painkillers.

While not all prescription painkillers are opioids, oxycodone, hydrocodone and other opioids are among those prescription painkillers generally most likely to be misused — compared with painkillers like nonsteroidal anti-inflammatory drugs, which typically aren’t thought to be addictive.

“For this reason, I think these [prescription painkiller data] are very good proxies for what we want to capture,” Cesur says.

Combat exposure is also associated with higher rates of heroin use, according to this paper. Looking at a different dataset, the authors find deployed service members who saw combat used heroin at a 1.4 percentage point higher rate than deployed service members who didn’t engage with enemy fighters. The authors identified the largest effects among service members in the Army, Marines and Navy, relative to service members in the Air Force. The government cost of treating active-duty service members and veterans who misuse heroin is nearly $500 million per year, the authors conservatively estimate.

Enlisted personnel bear the brunt

The U.S. military has two distinct career tracks: enlisted personnel and commissioned officers. One of those tracks bears the brunt of the opioid crisis in the military, this research finds.

Enlisted personnel perform tasks. They usually receive specialized training, and their specialties can vary widely. Enlisted personnel may scout a battlefield, or service biomedical equipment, or care for government-owned animals or perform any number of other specialties. A four-year degree is not required to enlist.

Commissioned officers serve primarily as management. They handle operations and strategy and give orders to lower-ranked officers and enlisted personnel. Each branch of the military has slightly different paths toward becoming an officer, but most include having or obtaining a four-year college degree.

In addition to having more formal education, officers also typically earn more money than enlisted personnel.

Enlisted personnel account for nearly all of the association between combat exposure and painkiller misuse, the authors find. Of the nearly 2.8 million service members who have served overseas since 9/11, 86% were enlisted, according to a 2018 analysis by the RAND Corporation.

“We find the effects among officers are almost zero,” Cesur says. Younger enlisted service members, age 18 to 24, who saw combat are also more likely to have misused painkillers, the authors find.

Data sources

The authors draw their findings from two surveys of military service members.

The first is the National Longitudinal Study of Adolescent and Adult Health, also called Add Health. This nationally representative survey originally interviewed about 20,000 adolescents in grades 7-12 during the 1994-1995 school year. Researchers asked about kids’ social and economic backgrounds, their performance in school and their psychological and physical well-being. They followed up with the original respondents during 2007-2008.

From Add Health, the authors analyzed a sample of 482 men aged 28 to 34 who reported actively serving in the military during the Iraq and Afghanistan wars in the early- and mid-2000s. Detailed socioeconomic information allowed the authors to study respondents who had similar upbringings. This sample led to the finding that prescription painkiller misuse was 7 percentage points higher among service members whose units were deployed to combat zones and engaged with enemy fighters.

The other, much larger sample was the 2008 Department of Defense Health and Related Behaviors Survey. This survey included nearly 30,000 active-duty service members aged 18 to 50. The authors’ sample included responses from 11,542 soldiers deployed overseas who provided information on recent prescription painkiller misuse. Respondents were also asked about other illicit drug use.

This sample led to the finding that heroin use is higher among service members who experience combat, and to the broader finding that enlisted personnel account for almost all of the link between combat exposure and painkiller misuse.

Men made up more than three-fourths of enlisted personnel who saw combat and responded to the DOD survey. Before 2013, women were not allowed to take up many frontline positions.

Injury, easy supply and peers

The authors reason that soldiers might start using opioids for their original medical purpose: when warzone service members are injured, opioids can help manage their pain.

Post-traumatic stress disorder also explains a big chunk of the relationship between combat exposure and painkiller abuse, Resul says. Traumatic events that military personnel experience, even among those who don’t serve directly on the front lines, can increase opioid misuse, according to the paper. In the authors’ DOD survey sample, 10% of active-duty deployed service members had PTSD.

Another reason for opioid misuse among military personnel who saw combat could be that cheap, high-quality opioids were available in the very places service members were deployed in the 2000s. Opium poppy cultivation in Afghanistan grew steadily in the years after 9/11, according to data from the United Nations Office on Drugs and Crime.

“Opium production in Iraq was much rarer than in Afghanistan, but production in Iraq began to grow in the aftermath of Operation Iraqi Freedom,” the authors write. “Production appears to have accelerated during the period just before and during the so-called ‘surge’ of U.S. Armed Forces to Iraq in 2007-2008.”

There may also be peer effects at play.

“People go to combat zones and then see their colleague is using opioids because he is stressed,” Cesur says. “So that may be another pattern. Humans are social creatures and we copy from each other.”

Veterans at risk

Programs aimed at reducing painkiller prescriptions to soldiers and veterans appear, so far, to be working.

Opioid prescriptions from Department of Veterans Affairs doctors fell more than 40% from 2012 to 2017, according to the authors. This coincides with the VA’s Opioid Safety Initiative, which began in 2013 and aims to educate healthcare providers on the benefits and risks of prescribing opioids.

The authors note that, “the reduction in opioid prescriptions to curb abuse may have the unintended consequence of reduced pain abatement for opioid users who do not suffer from addiction,” and that “sudden negative shocks to prescription painkillers could induce veterans to more dangerous, and perhaps deadly, forms of opioid use such as heroin or fentanyl if these drugs are substitutes.”

Despite fewer painkiller prescriptions, the opioid overdose death epidemic among veterans is still very real — and appears to be getting worse. After troop surges in Afghanistan and Iraq in the late 2000s, opioid use disorders among veterans rose 55%, according to data the authors cite from the VA.

Veterans broadly are twice as likely to die from accidental drug overdoses, according to one widely and recently cited study analyzing data from 2005 and published in 2011 in the journal Medical Care.

More recent research in the American Journal of Preventive Medicine bolsters the premise that veterans remain particularly vulnerable to addiction. The rate of opioid overdose deaths among veterans in 2016 increased 65% from 2010, according to that paper — even as the percentage of veterans who received prescriptions for opioids in the three months before their deaths fell from 54% in 2010 to 26% in 2016.

The authors of the new NBER paper cite evidence suggesting that medical marijuana could be an effective substitute for opioids in treating chronic pain. Medical marijuana may not play a straightforward role in easing the broader opioid epidemic, however. Research in the Proceedings of the National Academy of Sciences from just a few months ago found — contrary to prior research — that opioid overdose death rates increased by nearly a quarter in states with legal medical marijuana.

Can medical marijuana really play a role in easing the nation’s opioid epidemic? Here’s what the most recent research says. Plus, see the parts of the country where opioids are prescribed the most. And, America’s other drug epidemic. Last but not least, don’t miss these 10 rules for reporting on war trauma survivors, created in collaboration with our friends at The War Horse.

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