New research published today in the journal JAMA Psychiatry found that using marijuana as an adult is not associated with a variety of mood and anxiety disorders, including depression and bipolar disorder.
This is a challenge to some previous research which has shown that marijuana use is associated with depression and anxiety.
The researchers examined the records of nearly 35,000 U.S. adults who participated in the National Epidemiologic Survey on Alcohol and Related Conditions. They examined the prevalence of marijuana use among the study participants in 2001 and 2002, then checked on the participants’ rates of mental-health problems three years later in 2004 and 2005.
After controlling for a variety of confounding factors, such as socio-demographic characteristics, family history and environment, and past and present psychiatric disorders, the study found that “cannabis use was not associated with increased risk for developing mood or anxiety disorders.”
Don’t break out the celebratory blunt just yet, though. The study did find an association between marijuana use and later substance-use disorders, such as abuse of and dependence on alcohol, tobacco, marijuana and other drugs. But this isn’t necessarily surprising: It’s fairly obvious that if you use a substance, you’re putting yourself at risk of a substance-use disorder.
People who use one drug often use others — think of the classic beer-and-cigarette combo. This is as true of marijuana as it is of, say, alcohol. “The findings concerning cannabis raise the question of whether alcohol use also contributes to the risk of subsequent substance use disorders,” lead author Mark Olfson of Columbia University said in an email. But that issue is beyond the scope of the current study, he added.
The findings on mental health are more interesting, given the conflicting picture portrayed by previous research. But Olfson and his colleagues think some prior evidence of links between marijuana and psychiatric disorders could be due more to confounding factors than anything else.
Read the Rest