April 2, 2013 - People
with mental illnesses are more than seven times more likely to use cannabis
weekly compared to people without a mental illness, according to researchers
from the Centre for Addiction and Mental Health (CAMH) who studied U.S. data.
Cannabis is the most
widely used illicit substance globally, with an estimated 203 million people
reporting use. Although research has found links between cannabis use and
mental illness, exact numbers and prevalence of problem cannabis use had not
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,”
said Dr. Shaul Lev-ran, Adjunct Scientist at CAMH and Head of Addiction
Medicine at the Sheba Medical Center, Israel.
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
said Lev-ran, who conducted the research as a post-doctoral fellow with the Social
Aetiology of Mental Illness (SAMI) Training Program at CAMH.
also found that individuals with mental illness were 10 times more likely to
have a cannabis use disorder.
In this new study, published
in the journal Comprehensive Psychiatry,
CAMH researchers analyzed data from face-to-face interviews with over 43,000
respondents over the age of 18 from the National Epidemiologic Survey on
Alcohol and Related Conditions. Using structured questionnaires, the
researchers assessed cannabis use as well as various mental illnesses including
depression, anxiety, drug and alcohol use disorders and personality disorders, based
on criteria from the Diagnostic and Statistical Manual of Mental Disorders
Among those will
mental illness reporting at least weekly cannabis use, rates of use were
particularly elevated for those with bipolar disorder, personality disorders
and other substance use disorders.
In total, 4.4 per cent
of individuals with a mental illness in the past 12 months reported using
cannabis weekly, compared to 0.6 per cent among individuals without any mental
illness. Cannabis use disorders occurred among 4 per cent of those with mental
illness versus 0.4 per cent among those without.
Researchers also noted
that, although cannabis use is generally higher among younger people, the association
between mental illness and cannabis use was pervasive across most age groups.
They emphasize the
importance of screening for frequent and problem cannabis use among those with
mental illness, so that targeted prevention and intervention may be employed.
This study was funded
through the SAMI Training Program of the Canadian Institutes of Health Research
The Centre for
Addiction and Mental Health (CAMH) is Canada's largest mental health and
addiction teaching hospital, as well as one of the world's leading research
centres in its field. CAMH combines clinical care, research, education,
policy development and health promotion to help transform the lives of people
affected by mental health and addiction issues. CAMH is fully affiliated with
the University of Toronto, and is a Pan American Health Organization/World
Health Organization Collaborating Centre. For more information, please visit www.camh.ca.
Media contact: Michael
Torres; (416) 595-6015; firstname.lastname@example.org.