A dried flower bud of the Cannabis plant. Credit: Public Domain

With more states legalizing marijuana for medical and recreational use, there are renewed clinical and policy concerns about the mental health effects of the drug.

In a new study published online by JAMA Psychiatry, Mark Olfson, M.D., M.P.H., of the Columbia University Medical Center/New York State Psychiatric Institute, New York, and coauthors examined marijuana use and the risk of mental health and in the general population. The study used a nationally representative sample of 34,653 U.S. adults interviewed three years apart in the National Epidemiologic Survey on Alcohol and Related Conditions.

Analysis by the authors suggests marijuana use by adults was associated with increased risk of developing alcohol and drug use , including , at three years of follow-up. However, use was not associated with increased risk for developing mood or anxiety disorders.

Although the study cannot establish a causal association between using cannabis and the new onset of disorders, the authors conclude, "these adverse psychiatric outcomes should be taken under careful consideration in clinical care and policy planning.".

More information: JAMA Psychiatry. Published online February 17, 2016. DOI: 10.1001/jamapsychiatry.2015.3229

Journal information: JAMA Psychiatry