Marijuana addiction has risen among Veterans Affairs patients since 2005, with veterans who have psychiatric disorders most at risk, new research has found.
A study published last Wednesday in the American Journal of Psychiatry found that the addiction -- a diagnosis called cannabis use disorder -- more than doubled among veterans in the VA health system between 2005 and 2019, with veterans diagnosed with at least one psychiatric disorder seeing greater incidence and increases.
Cannabis use disorder is a condition where users struggle to stop consuming marijuana despite it causing health or social problems in their lives, according to the Centers for Disease Control and Prevention. Among those with mental health conditions, veterans with more severe mental conditions like bipolar disorder or illnesses along the psychotic spectrum saw the sharpest increases.
Marijuana has become legal for medicinal use in 38 states and for recreational use in 24 states, the District of Columbia and two territories. Nearly half of Americans believe it is beneficial for treating stress and anxiety.
But according to some studies, between 20% and 30% of people who use marijuana will develop cannabis use disorder. The reliance can negatively affect a patient's life, either by developing tolerance, spending a significant amount of time obtaining and using marijuana, disrupting work and relationships, causing risky behavior such as driving while impaired, and eliciting cravings.
For the study, researchers with the New York State Psychiatric Institute, the Department of Psychiatry at Columbia University, the VA Puget Sound Health Care System in Washington state and elsewhere, examined Veterans Health Administration electronic health records from 2005 to 2014 and 2016 to 2019.
The research found that over time, cannabis use disorder diagnoses in the first time period increased slightly, by a third of a percentage point, to .66% in patients who did not have a mental health diagnosis, and rose from 2.5% to 4.7% for those with a psychiatric diagnosis.
In the second time period, which used a different definition for cannabis use disorder under new medical diagnostic codes established by the International Statistical Classification of Diseases and Related Health Problems, the diagnoses of cannabis use disorder reached 4.68% among VA patients with a known psychiatric disorder and .57% among vets without a mental health diagnosis.
When broken down by major mental health diagnoses, those with bipolar and psychotic spectrum disorders had nearly double the rates of the diagnoses than those with anxiety, post-traumatic stress disorder or depression.
While the study did not delve into why diagnoses are on the rise or why those with psychiatric conditions are disproportionately affected, Dr. Ofir Livne, an assistant professor of clinical psychiatry at Columbia University and research scientist at New York State Psychiatric Institute who worked on the study, said a number of factors may have contributed to the increases.
In an interview with Military.com on Monday, Livne said mental health conditions and substance abuse often go hand in hand, and with the changing attitudes and legalization of marijuana in many locations, it may be seen as a safer or more effective alternative to alcohol or other drugs.
The cannabis available now also is more potent than it was just a decade ago, so users are "more likely to get addicted and develop substance abuse disorder," Livne said.
Another interesting finding, according to Livne, was that during the first time frame, the greatest increases in cannabis use disorder diagnoses were seen in patients under 35, while beginning around 2016, rates rose significantly for those older than 65.
Livne said those who are older than 65 -- Baby Boomers -- grew up in more liberal times and may be more inclined than previous generations to use marijuana. And with the increased potency, older people, who may not metabolize the drug as they would have when they were younger, may be more at risk for developing cannabis use disorder.
"People who are older have more medical problems, and with cannabis being perceived as legitimate means of treating medical problems, more and more people of that age are more willing to try it," Livne said.
A study published earlier this year of VA patients found that state laws on medicinal and recreational marijuana played a "significant role" in increases in cannabis use disorder diagnoses, especially in older patients.
Medical legalization accounted for 5% of the overall increase in cannabis use disorders in those states while recreational legalization accounted for about 10%, according to the research.
"We're going to see, more and more, an increase in cannabis use in this age group and subsequently increases in cannabis use disorder," said Livne, who also worked on the state comparison study.
The most recent study was not without its limitations. It only looked at the VA health-care population and did not represent the veteran population as a whole, and it also relied on data from electronic health records that could include disparities in diagnosis and did not contain any information on frequency or motive for using the drug, such as for recreation or self-medication.
Since 2014, the Department of Veterans Affairs has been under pressure from some members of Congress to require its physicians to prescribe medical marijuana in states where it is legal.
This year, the Senate has approved a bill that includes a provision to allow VA doctors to make recommendations on medical marijuana, and legislation similar to that passed in the House earlier this year.
To become law, the provision in the military construction, veterans affairs and related agencies appropriations bill must survive a conference between the two chambers, followed by another vote in the House and Senate.
Studies on the effectiveness of marijuana for treating veterans with PTSD have shown mixed results. The most scientifically rigorous study, which compared various levels of cannabis containing the active ingredients in the plant with a placebo, showed no significant reductions in PTSD symptoms between a placebo and cannabis in 80 veterans enrolled in the research.
A follow-on study by the same researchers showed a significant reduction in PTSD symptoms in those who used marijuana containing both delta-9-tetrahydrocannabinol, known as THC, and cannabidiol, known as CBD, but the trial did not have a placebo group to compare.
The VA recently has stepped back from conducting research on cannabis as a potential treatment for psychiatric conditions in veterans, even as it is encouraging researchers to study other drugs, such as MDMA and psilocybin, to treat mental health conditions.
Earlier this year, VA published new clinical guidance recommending against marijuana to treat veterans with PTSD. VA cited the lack of scientifically rigorous research as well as evidence that shows medical marijuana impairs memory, IQ, attention and driving ability," in addition to being linked with psychosis and other adverse psychiatric outcomes, as its reasons against its use.
"The body of evidence had significant limitations, including a lack of randomized, controlled, methodologically sound clinical trials; small sample sizes, and selection bias," the VA working group on clinical guidelines wrote. "The benefits of cannabis were outweighed by the potential serious adverse effects."