Vivian N. Onaemo, Ph.D., M.P.H., M.B.B.S., of the Government of Saskatchewan Ministry of Health in Reginia, Canada, and colleagues analyzed data from eight articles from six epidemiological surveys published from January 1980 through July 2020. There were approximately 177,000 respondents among all six surveys, and the surveys were largely conducted in the United States and Australia.
The odds of having major depression were 3.22 times higher in people with cannabis use disorder compared with those without cannabis use disorder. Onaemo and colleagues noted several possible reasons for this, including cannabis-induced changes in brain chemistry and genetic or environmental vulnerabilities that predispose some people to mental health problems and substance use disorders.
The odds of having generalized anxiety disorder were 2.99 times higher in people with cannabis use disorder compared with those without cannabis use disorder. The researchers wrote that chronic cannabis use could lead to the development of anxiety symptoms and that early cannabis use may affect cognitive function in adolescents, thereby predisposing them to the development of anxiety.
The researchers added that some people with depression or anxiety may self-medicate with cannabis for its calming or euphoric effect.
“However, irrespective of the pathway that led to the comorbid state and the high prevalence of the comorbidity, it does appear that once an individual has developed both [cannabis use disorder and depression or anxiety], a vicious cycle may be at play where each disorder maintains or exacerbates the other,” they wrote.
“Given the increasing prominence of cannabis use along with ongoing changes in many countries’ cannabis legalization, it is imperative to mitigate the serious health-related harms of [cannabis use disorder], such as increased risk of comorbid anxiety or depression; high risk of myocardial infarction, stroke, and transient ischemic attacks; increased [emergency department] visits and fatal car accidents; and crime,” the researchers concluded.
For related information, see the Psychiatric News article “Cannabis Use Disorder Linked to Increased Heart, Stroke Risk in Youth.”