The percentage of Americans who reported using marijuana more than doubled between 2002 and 2013, with nearly as large an increase in marijuana use disorders during
that time period, a new study has found.
The research also showed that 2.5 per cent of adults nearly 6 million people experienced marijuana use disorder in 2012-13, while 6.3 per cent had met the diagnostic criteria for the disorder at some point in their lives.
The study, conducted by researchers from Columbia University and US National Institute on Alcohol Abuse and Alcoholism (NIAAA) found that marijuana use disorder is often associated
with other substance use disorders, behavioural problems, and disability, and goes largely untreated.