Marijuana Use Tied to Higher Odds for Thoughts of Suicide

Young adults who use marijuana appear to have an increased risk of suicidal thoughts and attempted suicide, according to a new study from the U.S. National Institute on Drug Abuse (NIDA).

In fact, the risk that someone between 18 and 34 will think about, plan for or attempt suicide increases with the amount of marijuana they use, according to results published June 22 in the journal JAMA Network Open.

Even occasional pot use was associated with a greater risk of suicidal thoughts, plans and attempts compared to no pot use at all, and the risk rises as people use more often, results show.

Risk also increased regardless of whether the cannabis user suffered from depression, although pot smokers with depression had an overall greater risk of suicidality, according to the study.

Also, women were more strongly affected by this link than men.

"Regardless of whether you had a history of depression or not, cannabis significantly increased the risk of suicidal behavior. It wasn't a small effect. It was a large effect," said Dr. Nora Volkow, director of NIDA. "I expected an association, but it just took me aback."

The number of U.S. pot users more than doubled between 2008 and 2019, rising from 22.6 million to 45 million, researchers said in background notes. The number of daily or near-daily users almost tripled during the same period, rising from 3.6 million to 9.8 million.

Over the same span, the number of folks who had recently suffered major depression rose from 14.5 million to 19.4 million, and the number of suicidal people increased from 8.3 million to 12 million, researchers said. Annual deaths by suicide rose from about 35,000 in 2008 to nearly 45,900 in 2019.

To study possible links between suicidality and pot smoking, Volkow's team analyzed a decade's worth of data from a nationwide survey on drug use.

Suicidality tracked with a person's level of marijuana use, researchers found.

For example, among people not suffering from depression in the 2018-2019 survey:

• 14% of men and 18% of women with cannabis use disorder thought about suicide, compared with 4% for either sex not diagnosed with problematic pot use.

• Nearly 9% of men and 13% of women who were daily or near-daily users thought about suicide, compared with 6.5% of men and 9% of women who were occasional users and 3% of both sexes who were non-users.

Suicide planning and attempts tracked the same way based on level of use, and the effect was amplified in people with depression. Among the depressed:

• 51% of men and 57% of women with cannabis use disorder thought about suicide, compared with about 40% for either sex not diagnosed with problematic pot use.

• 56% of men and 55% of women who were daily or near-daily users thought about suicide, compared with 43.5% of men and 47% of women who were occasional users and 38% of men and 34% of women who were non-users.

This is just an association, and it could run either way, experts said.

It might be that people prone to suicide turn to marijuana as a potential form of relief, rather than pot spurring them to suicidal thought and action, said Dr. Elie Aoun, an addiction psychiatrist with the Columbia University College of Physicians and Surgeons in New York City.

"We have to think about whether it's the cause or the consequence, or just factors that happen to coexist at the same time," Aoun said.

It's also possible that suicide and marijuana use share some common genetic risks, Volkow said, and just happen to occur at the same time among people carrying these genes.

Mitch Earleywine, an advisory board member for the advocacy group NORML, thinks this is a "self-medication issue."

"We happen to be looking at data during a time when both suicidal ideation and cannabis consumption have increased, but the notion that one causes the other seems less likely than a spurious link among each of these and a lot of other economic, social, and legal issues," said Earleywine, a professor of psychology at the State University of New York at Albany.

"Anyone struggling with suicidal ideation should certainly reach out for help, and cannabis alone likely offers little in that department, but the idea that cannabis use is leading to these thoughts has received no support here," he said.

However, Volkow and Aoun said it would be premature to dismiss marijuana use as an influence on a person's risk of suicide.

Marijuana can increase a person's feelings of depression and anxiety by interfering with the brain's ability to cope with these feelings, Volkow said.

"One of the things marijuana does is it decreases anxiety acutely," she said. "But once you're no longer intoxicated, you are less able to modulate your anxiety. During that period of withdrawal, you will be more susceptible to enhanced sensitivity to stressors."

Pot use also increases impulsive behavior, and for some people suicide is an essentially impulsive act, Volkow added.

"You more or less feel OK and then all of sudden there's this urgent need to kill yourself," she said. "Those impulsive acts of suicide have been associated in the past with marijuana."

There's also the possibility that pot and other drugs act as a form of "chemical procrastination," allowing people to ignore troubling feelings for which they should seek professional help, Aoun said.

"You have something that you don't want to deal with, so rather than dealing with it you're taking a chemical," he said. "The more you delay, the harder it becomes. If you haven't dealt with your problems in one day or in two days or in three days, you're going to have this idea that your problems are not fixable -- not because you've tried and failed, but just because days have passed and you haven't done anything."

The increase in marijuana's use as a medicine could be amplifying this effect, Aoun added.

"There's a lot of overhyping of the potential clinical benefits of marijuana, and that's getting a lot of people who would have never used marijuana to start using," he said. "This is what scares me with marijuana, that a lot of the information that's being spread on the internet is not necessarily accurate, yet it's being spread very aggressively."