Washington: People with mental illnesses are more than seven times more likely to use cannabis weekly compared to people without the condition, US researchers say.
Researchers at the Centre for Addiction and Mental Health (CAMH) also found that individuals with mental illness were 10 times more likely to have a cannabis use disorder.
In this new study, 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 (DSM-IV).
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.
The study has been published in the journal Comprehensive Psychiatry.