Young Cannabis Consumers with Mood Disorders at Higher Risk of Self-Harm, Study Finds

Young people with mood disorders who also struggle with problematic cannabis use are at a higher risk for self-harm, according to new research from the Ohio State University Wexner Medical Center and College of Medicine.

In their new study, published in JAMA Pediatrics, the researchers also found associations between this group and higher risks of death via an unintentional overdose, homicide, and all-cause mortality.

As the study was purely observational, the researchers do not suggest any type of causality or mechanism behind these associations. However, they do suggest that a national study specifically examining mortality risks in young people with comorbid mood disorders and cannabis use disorder (CUD) could help to better inform policy and treatment decisions.

CUD seen in more than 10 percent of youths with diagnosed mood disorders

In total, the study looked at data from more than 200,000 people aged between 10 and 24 years old, compiled from Ohio Medicaid claims linked with death certificate data. The claims came between July 1, 2010, and December 31, 2017.

The Ohio state researchers examined the patient records for information relating to physician-diagnosed CUD and assessed the incidence of non-fatal self-harm as well as all-cause mortality, suicides, unintentional overdoses, car accidents, and homicide to look for any apparent relationships.

“We also found that cannabis use disorder was significantly associated with self-harm, including death by unintentional overdose and homicide,” lead author Cynthia Fontanella, an associate professor in psychiatry and behavioral health at Ohio State University, explained in a statement. “Unfortunately, while this observational study calls attention to these associations, it is unable to contribute to our understanding of causality or mechanism.”

Fontanella and her colleagues found documented cases of cannabis use disorder (CUD) in more than 10 percent of the patients in the study. These patients with CUD were also more likely to be older, Black, male, and have a prior history of self-harm, mental health service use, or a diagnosis of bipolar disorder or other mood disorders.

“Marijuana use and addiction is common among youth and young adults with mood disorders, but the association of this behavior with self-harm, suicide and overall mortality risk is poorly understood in this already vulnerable population,” said Fontanella.

“These findings should be considered as states contemplate legalizing medical and recreational marijuana, both of which are associated with increased cannabis use disorder.”

Understanding CUD

Researchers already know that teenagers and young adults in areas with legal cannabis access are at a higher risk of developing problematic cannabis use behaviors. One 2019 study found a relative increase of 25 percent in teenage problematic use in Alaska, Colorado, Oregon, and Washington after their state-level legalizations. The same study also noted that the prevalence of usage behaviors matching the definition of CUD jumped from 0.9 to 1.23 percent in adults aged 26 and over.

Following the publication of this study, Ian Hamilton, a senior lecturer in addiction at the University of York, told Analytical Cannabis that this cannabis usage study indicates the crucial need for further study on the ongoing effects of cannabis legalization once these policies are passed.

“I don't think this study shows that access to cannabis shouldn't be permitted, but it does show that, for the small proportion of users who develop problems, support services need to be adequately funded and available – something other states and countries should factor in when thinking of changing their cannabis policies,” he said.

The study’s lead author, Magdalena Cerdá, echoed a similar sentiment in a statement accompanying the study publication.

“There are, indeed, important social benefits that legalizing marijuana can provide, particularly around issues of equity in criminal justice,” explained Cerdá.

“Our findings suggest that as more states move toward legalizing marijuana for recreational use, we also need to think about investing in substance use prevention and treatment to prevent unintended harms – particularly among adolescents.”

Indeed, such efforts to combat cannabis dependence are already in motion. One of the more novel approaches, recently trialed in a study published in Lancet Psychiatry, involved high doses of CBD to help reduce excessive cannabis use.

“We know that CBD has contrasting effects to THC on the endocannabinoid system,” study author Dr Tom Freeman told Analytical Cannabis following its publication. “We know that THC is a partial agonist at cannabinoid receptors. But CBD has minimal direct activity at cannabinoid receptors.”

“At the same time, it does have properties that could be helpful in treating cannabis use disorder, such as inhibiting the effects of other ligands acting on the CB1 receptor and increasing endocannabinoids. And this is a potential mechanism through which it could be acting to alleviate the cannabis use disorder and help people cut down their use.”