Cannabis use is associated with an increased risk for several substance use disorders, new research suggests.
The study, based on 35,000 American adults, found that marijuana use by adults was associated with an increased risk of developing alcohol and drug use disorders, including nicotine dependence, after three years of follow-up.
But cannabis use was not associated with increased risk for developing mood or anxiety disorders, according to the paper, published in the journal JAMA Psychiatry.
The authors wrote: "Our study indicates that cannabis use is associated with increased prevalence and incidence of substance use disorders. These adverse psychiatric outcomes should be taken under careful consideration in clinical care and policy planning."
Dr Amir Englund, a post-doctoral researcher in psychopharmacology at the Institute of Psychiatry, Psychology and Neuroscience at King's College London, commented: "The present study is a large study exploring the effects of cannabis use on future problems such as anxiety, depression and drug and alcohol addiction.
"They found that use of cannabis was related to increased risk of later addiction to alcohol, cannabis and other drugs. Cannabis was not related to anxiety or depression at follow-up.
"Of course a study such as this is unable to ascertain causality between cannabis use and later drug addiction, merely that a relationship exists."