with NIDA Deputy Director Wilson M. Compton, MD, MPE 

 

A NIDA-led study published in JAMA Network Open in late June 2021 is raising questions about the association between cannabis use and suicidal ideation. While the researchers did not examine causation or medical cannabis, they did find trends regarding increased suicidal ideation and increased cannabis use in the decade between 2008 and 2019. The study, conducted by researchers at the National Institute on Drug Abuse (NIDA), may lead to increased national attention on the growing mental health crisis.

Suicidality Trends, Depression, and Sex

NIDA’s survey-based study examined data from 281,650 adults aged 18 to 34 years who participated in the agency’s National Surveys on Drug Use and Health from January 1, 2008, to December 31, 2019.1 Researchers focused on the association between cannabis use and suicidal ideation, planning, and attempts (eg, suicidality).

Cannabis use was divided into four categories: no use, non-daily use, daily use (300 days/year or more), and the presence of cannabis use disorder (CUD). A distinction was also made between participants with major depressive disorder (MDD), assessed by the prevalence of major depressive episodes (MDE). Criteria for CUD and MED were based on DSM-IV diagnostic criteria.

Major Depression: Links to Suicidality and Cannabis Use Disorder on the Rise

The survey was conducted in response to an upward trend in prevalence rates of major depressive disorder, CUD, and suicidal ideation. Between 2008 and 2019, the number of adults with past-year MDE increased from 14.5 million to 19.4 million.2,3 The number of adults experiencing suicidal ideation increased from 8.3 million to 12 million,2,3and the number of adults who died by suicide increased from 35,045 to 45,861.4

During the same timeframe, the number of adults with past-year CUD nearly doubled, from 22.6 million in 2008 to 45.0 million in 2019, and the number of adults who used cannabis daily nearly tripled, from 3.6 million to 9.8 million.2,3

Suicidal Ideation in Women Rose Between 2008 and 2019, Nearly Doubling in Those with Low Incomes

The NIDA survey also queried sociodemographic characteristics. During the 2008-2019 decade, there were reported increases in suicidal ideation among all sociodemographic subgroups. One notable highlight was suicidal ideation among women, which increased from 5.9% to 9.9 %. For the subgroup with a family income equal to or less than $20,000, suicidal ideation increased from 6.5 % to 11.3%. In women of families with an income equal to or greater than $75,000, suicidal ideation increased as well, rising from 4.5 % to 7.4%

The researchers reported an association between cannabis use and suicidal ideation with or without the presence of major depressive episodes. And while the results did not demonstrate a causative relationship between cannabis use and suicidality, it showed how broad factors are increasing suicide rates in nearly all populations.

Professional Takeaways

NIDA Deputy Director Compton’s Take on the Results

Wilson M. Compton, MD, MPE, NIDA’s deputy director, tells Psycom Pro, “As a psychiatrist, I am really concerned about these increases in suicidality. We did this study to see what role cannabis might play, and while we see a strong association, this clearly is not the only factor. I think we must start looking at broad social changes as well as any other environmental factors that might play a role. No one has completely explained these increases in suicidality.”

According to the NIH National Institute of Mental Health (NIMH), depression and mental health disorders are one of the greatest risk factors for suicide.5 At the same time, America’s Mental Health 2018 reported that, despite 56% of Americans seeking mental health services, these services are insufficient and inequitable.6 Self-treatment with cannabis, as well as other drugs and alcohol is something providers should be increasingly aware of as they assess and treat patients.

Cannabis Benefits for Anxiety and Chronic Pain Remain Unknown

What about medical cannabis use in patient populations with anxiety disorders and chronic pain – both of which are associated with higher rates of suicidality?7,8 A growing body of research indicates that cannabis may relieve chronic pain and comorbid mental health disorders, especially where traditional pharmacological methods have failed.9 The efficacy of cannabis for anxiety disorders is less clear, with studies seeming to favor CBD only or CBD predominant products10 and not recommending for individuals at risk of psychosis.11 (See also, cannabis for managing symptoms of PTSD and ADHD).

“Our study does not examine medical cannabis in any way,” clarified Dr. Compton. He added, “I do think it raises enough concern that when cannabis is being used, clinicians should be cautious and pay attention to unexpected developments of depression and unexpected developments of suicidality.”

Perhaps most important is that there are simply not enough quality studies available on the effects and/or benefits of cannabis use (partly due to its status as a Schedule 2 narcotic). Prescribers and clinicians should remain aware of self-treatment with cannabis, which may have unexpected side effects, especially when it is not federally regulated.

Suicidality Increased in those without a Mental Disorder

It is worth noting that in the NIDA survey, among those with no cannabis use and no major depressive episodes, the reported increase in past-year suicidal ideation was 3.3 % in 2019, up slightly from 2.3% in 2008. In participants with major depressive episodes who did not use cannabis, past-year suicidal ideation was 35.0% in 2019, up from 27.7% in 2008. And in participants who used cannabis daily and had major depressive episodes, suicidal ideation was 52.6% in 2019, up from 47.6% in 2008.

The roots of these increases are most certainly multifactorial. Environmental factors, inclusive of substance use, are a crucial part of the dialogue with patients. The fact that cannabis has become legalized – both recreationally and medically – in several states since 2008, may also be a contributing factor to increased substance use.

“We approached this study thinking that, maybe, it’s these markedly high increases in cannabis use that explain these increases in suicidality in young adults,” noted Dr. Compton. “While we see a strong relationship to cannabis use and suicidality, we still see increases in suicidality amongst those not using cannabis.” Environmental factors, such as social support networks, job security, racial segregation, poverty, and family support all play a role. One thing this study makes painfully clear is the nationwide need for a better understanding of mental health disorders, and suicidality.

References
Last Updated: Jul 9, 2021