Mental Illness And Marijuana Use By The Numbers
April 3, 2013

Cannabis Use Higher Amongst Those With Mental Illnesses

redOrbit Staff & Wire Reports - Your Universe Online

Individuals who have mental illnesses are seven times more likely to use marijuana on a weekly basis than their non-mentally ill counterparts, researchers from Canada´s Centre for Addiction and Mental Health (CAMH) claim in a new study.

The researchers analyzed data compiled from a series of face-to-face interviews with more than 43,000 Americans over the age of 18 who participated in the National Epidemiologic Survey on Alcohol and Related Conditions.

They discovered that 4.4 percent of individuals with mental illnesses during the past 12 months said that they had used cannabis weekly, compared to 0.6 percent among those who did not have mental illness.

In addition, they discovered that individuals with mental illness were 10 times more likely to have a cannabis use disorder that those without mental illnesses — 4 percent compared for the former group versus 0.4 percent for the latter group. Weekly marijuana usage rates were particularly elevated among those suffering from bipolar disorders and personality disorders, as well as those with additional substance use disorders, the investigators said.

His team´s research was sponsored by the Social Aetiology of Mental Illness (SAMI) Training Program of the Canadian Institutes of Health Research (CIHR) and has been published in the journal Comprehensive Psychiatry.

“We know that people with mental illness consume more cannabis, perhaps partially as a way to self-medicate psychiatric symptoms, but this data showed us the degree of the correlation between cannabis use, misuse, and mental illness,” Dr. Shaul Lev-ran, Adjunct Scientist at CAMH and Head of Addiction Medicine at the Sheba Medical Center in Israel, said in a statement.

“Based on the number [of] individuals reporting weekly use, we see that people with mental illness use cannabis at high rates. This can be of concern because it could worsen the symptoms of their mental illness,” he added. Lev-ran conducted the research while serving as a post-doctoral fellow in the CAMH SAMI Training Program.

The survey that served as the basis for the study used structured questionnaires which assessed each participant´s marijuana use. It also inquired about a variety of other mental illnesses including depression, anxiety, drug and alcohol use disorders, and personality disorders, the researchers said. Criteria for each condition were obtained from The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV).

According to CAMH, cannabis is the most widely used illicit substance in the world, with more than 200 million people reportedly using the drug. While previous research had found a link between marijuana use and mental illness, those studies did not investigate the precise numbers and overall prevalence of problem cannabis use, they added.