Cannabis use disorder or CUD is common among younger cannabis users with mood disorders such as bipolar disorder or major depression. But the association of CUD with self-harm and suicide hasn’t been fully explored, so researchers at Ohio State University's College of Medicine decided to investigate the issue in some more depth.
Their study was performed using Ohio Medicaid claims data linked to death certificate data. The analysis included 204, 780 youths aged 10-24 years who were diagnosed with a mood disorder between 2010 and 2017. The fate of the young people was then followed through and any self-harm event or death recorded.
The results showed that cannabis use disorder is a common comorbidity and risk marker for self-harm, all-cause mortality, and death by unintentional overdose and homicide among youths with mood disorders. Youths with CUD were around three times more likely to have non-fatally harmed themselves or committed suicide and 3.4 times more likely to have died through unintentional overdose.
It’s worth noting, however, that although CUD was associated with suicide in the unadjusted model, it was not significantly associated in adjusted models.
Prior studies show children with mood disorders are highly likely to use and abuse marijuana, partly because they don't like the side effects of many prescribed medications. But it could also be that using weed might contribute to the development of mood disorders in this first place: at this point, science is not sure which comes first.
The study acknowledges that though there is a clear association between cannabis dependence and negative outcomes, it can’t be said to be direct cause and effect.
However, in an explainer about the study, lead author Cynthia A. Fontanella, said the findings “should be considered as states contemplate legalizing medical and recreational marijuana, both of which are associated with increased cannabis use disorder”.