Are Marijuana Dependence and Depression Related?

By John Lavitt 04/06/16

The surprising results were from a Yale study which included a genome-wide analysis of more than 14,000 individuals.

Are Marijuana Dependence and Depression Related?
photo via Shutterstock

A new Yale study has identified specific genes that are linked with cannabis dependence, for the first time ever.

The researchers were able to link three genetic markers with symptoms of marijuana dependence. They performed a genome-wide analysis of more than 14,000 individuals, and looked for differences in the genomes of two groups: pot users who met the criteria for marijuana dependence and pot users who were not considered dependent. The Yale researchers initially sought to identify gene variants that significantly increase the risk for cannabis dependence, based on the idea that an addiction to pot can be inherited, like alcoholism.

The results of the study, published last Wednesday in JAMA Psychiatry, suggest these genetic markers are associated with marijuana dependence, but this does not prove that they actually cause marijuana dependence.

The researchers also found marijuana dependence, depression and schizophrenia may share genetic risk factors. "We were surprised to find a genetic risk overlap between cannabis dependence and major depression," said senior author of the study, Dr. Joel Gelernter, in a statement. This provides some insight into why addiction to pot and depression or schizophrenia may occur together.

The study also raises the question of whether certain mental illnesses might raise the risk for marijuana dependence as well. Past Fix contributor Maia Szalavitz said the study's findings could help explain why the majority of people who are considered addicted to pot tend to have a co-existing psychiatric condition as well, like schizophrenia.

While some may be quick to conclude that these findings are proof that marijuana causes depression, Szalavitz puts the study's results in plain terms. "[I]f certain genes raise risk for both conditions, this could make it look like marijuana addiction causes depression, she explained in TIME, "when in fact, some people at genetic risk for depression are simply more likely to smoke pot excessively, perhaps in an attempt to self-medicate."

Gelernter said the new findings will hopefully lead to a better understanding of the biology of marijuana dependence. And with further research, perhaps scientists will eventually be able to develop effective treatments to target marijuana use disorder.

"We hope our findings help bring more awareness to the public that cannabis use is often not benign and can lead to dependence, especially in individuals at high genetic risk," Gelernter told Live Science

Please read our comment policy. - The Fix

Growing up in Manhattan as a stutterer, John Lavitt discovered that writing was the best way to express himself when the words would not come. After graduating with honors from Brown University, he lived on the Greek island of Patmos, studying with his mentor, the late American poet Robert Lax. As a writer, John’s published work includes three articles in Chicken Soup For The Soul volumes and poems in multiple poetry journals and compilations. Active in recovery, John has been the Treatment Professional News Editor for The Fix. Since 2015, he has published over 500 articles on the addiction and recovery news website. Today, he lives in Los Angeles with his beautiful wife, trying his best to be happy and creative. Find John on Facebook, Twitter, and LinkedIn.