The claim: “A study was done, a post-mortem, so a retrospective study done, looking at autopsies and drug levels, what drugs were in the blood of veterans that committed suicide, and 70 percent had THC.” — State Sen. Donna Campbell, R-New Braunfels.
The statement was made during debate in the Texas Senate.
PolitiFact ruling: Pants on Fire. Campbell, who is an emergency room physician, suggested cannabis plays a role in suicide among veterans, but the study Campbell cited doesn’t seem to exist. Some research does exist on this topic, but experts question the validity of drawing a conclusion about the connection between marijuana use and suicide generally — let alone among veterans.
Discussion: Texas lawmakers this year voted to broaden the state’s medical marijuana program to include more qualifying conditions than just intractable epilepsy.
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Under the bill, which was signed into law, patients with several other conditions, including terminal cancers, autism and multiple sclerosis, will now be eligible to participate in the program.
During a debate in the Senate over the proposal, Campbell cited the statistic while arguing against including post-traumatic stress disorder in the bill. The disorder was ultimately not included in the bill that passed.
Campbell’s office did not respond to multiple requests for comment. We searched far and wide but could not find a study with results matching those she described.
A 2016 study by scientists from the Centers for Disease Control and Prevention that used data from the National Survey on Drug Use and Health found that the rate of suicidal thinking was more than nine times higher for veterans with drug problems than those without, with the majority involving marijuana abuse.
The study noted, however, that other factors, such as coping with post-traumatic stress, managing chronic pain conditions related to war injuries or adjusting to civilian life, could confound the association between the two.
What makes this subject so hard to study? One reason is suicide is a complex behavior with many aspects — from contemplation, to attempts — with or without a plan — to actual deaths, said Dr. Arpana Agrawal, professor of psychiatry at the Washington University School of Medicine who authored a study on cannabis and suicidal thoughts and behavior,
“(Researchers) might have asked only of individuals who report experiencing depression, although suicidal thoughts and behaviors are not just limited to depression,” Agrawal said. “In studies of completed suicide, little may be known about the substance use history over and above a toxicology report.”
Research also is lacking on cannabis use and suicide among veterans specifically.
A 2018 study conducted by Safe States Alliance, an injury and violence prevention national nonprofit, used data from the CDC’s National Violent Death Reporting System to analyze U.S. veteran and armed forces deaths from suicide.
The group’s study found 9 percent of victims had marijuana in their system. It did not show whether a victim had more than one substance in his or her system.
Sharon Gilmartin, deputy director of Safe States Alliance, said she wasn’t aware of a statistic like the one Campbell cited.
Gilmartin also cautioned against interpreting her organization’s studies or others that include toxicology data as definitively linking marijuana to suicide because of the nature of THC.
“It’s not quite like alcohol where you have a certain (blood alcohol content), and that directly links to impairment, then it goes away, and you’re kind of back to sobriety more or less,” Gilmartin said. “When you think about THC, it’s a different dose-response relationship, and it also has a different latency period, so it stays in your blood long after you’re impaired.”
There are also limitations to what such data can tell us, Agrawal said.
“While such studies show a correlation, it is difficult to know from data at one time point whether cannabis use is a causal factor,” she said. “Veterans are more likely to report cannabis use and are also at risk for suicide. But that doesn’t answer the question as to how the two are related.”
For example, she said, people who are vulnerable to suicide might use cannabis more often to self-medicate, or people who use cannabis more heavily might report more suicidal thoughts or alternatively, some other factor might influence the use of both cannabis and risk for suicide, such as trauma exposure.