• A study linked cannabis use to increased risks of suicidal ideation, suicide plans and suicide attempts
  • Risks were greater for women than for men, researchers found
  • Researchers said more studies are needed to better understand the relationship between cannabis use and suicidality

A new study from the National Institutes of Health has suggested that cannabis use may be linked to an increased risk of suicidality.

An analysis of the data of more than 280,000 young adults found higher rates of suicidal ideation, suicide planning and suicide attempts among those who used marijuana compared to those who did not use cannabis at all, according to a news release from the NIH.

The study's findings, published in the Journal of the American Medical Association, indicated that the increased risks were observed in men and women who used marijuana on both a daily and a nondaily (fewer than 300 days a year) basis, regardless of whether someone was also suffering from depression.

Nora Volkow, senior author of the study and director of the National Institute on Drug Abuse, part of the NIH, said that although the research did not prove that cannabis caused the increased suicidality, it could lead to future research in this direction.

"While we cannot establish that cannabis use caused the increased suicidality we observed in this study, these associations warrant further research, especially given the great burden of suicide on young adults," Volkow said. "As we better understand the relationship between cannabis use, depression, and suicidality, clinicians will be able to provide better guidance and care to patients."

Within the last decade, the number of adults in the U.S. who use marijuana has more than doubled, the report noted. This development came with a parallel increase in suicidality, the researchers found.

Volkow and her team analyzed data from 281,650 U.S. adults aged 18 to 35 years in the National Surveys on Drug Use and Health from 2008 to 2019.

Among those with depression in the survey, about 35% of people who did not use cannabis reported having suicidal ideation. This figure increased to 53% for those who used cannabis daily and 44% for those with nondaily cannabis use.

Among participants without a major depressive episode, about 3% of those who did not use cannabis had suicidal ideation. However, 9% who used marijuana daily and 7% who reported nondaily cannabis use had thoughts of suicide.

The numbers increased significantly when it came to women, according to the researchers. Women who used cannabis at any level were more likely to have suicidal ideation or report a suicide plan or attempt than men with the same levels of cannabis use, the study found.

Among those who did not suffer from depression, suicidal ideation was reported by 13.9% of women who used cannabis, while only 3.5% of women who did not consume marijuana reported having thoughts of suicide.

"Suicide is a leading cause of death among young adults in the United States, and the findings of this study offer important information that may help us reduce this risk," explained lead author Beth Han of the NIDA.

"Depression and cannabis use disorder are treatable conditions, and cannabis use can be modified. Through better understanding the associations of different risk factors for suicidality, we hope to offer new targets for prevention and intervention in individuals that we know may be at high-risk. These findings also underscore the importance of tailoring interventions in a way that takes sex and gender into account," Han concluded.

Customers queue on March 18, 2020, in front of a cannabis store in central Montreal, as coronavirus lockdowns triggered a brief surge in recreational use of the drug in Canada
Customers queue on March 18, 2020, in front of a cannabis store in central Montreal, as coronavirus lockdowns triggered a brief surge in recreational use of the drug in Canada AFP / Jacques LEMIEUX