According to an article in Nature and a study recently published in Nature Genetics, researchers have identified genes they believe are linked to cannabis addiction. They also found that some of the same genome regions are tied to health conditions including lung cancer and schizophrenia. The findings were discovered after an analysis of more that one million people’s genomes.

The study’s co-author, Dr. Daniel Levey, a medical neuroscientist at Yale, told Nature the finding shows that addiction to cannabis is “evidence that cannabis addiction could have substantial public health risks if the usage increases.”

Additionally, according to an article written about the study in Yale News, the research indicates links to “psychiatric disorders, abuse of other substances such as tobacco, and possibly even an elevated risk of developing lung cancer.”

Both the study and the Nature article point out the increasing legality of cannabis for recreational purposes, including in eight countries, and medicinal use in 48 countries. “But one-third of people who take cannabis end up becoming addicted or using the drug in ways that are damaging to their health.”

Earlier research suggests a genetic component in the links between problematic cannabis use and health challenges.

The data the researchers used came primarily from the U.S. Department of Veterans Affairs’ Million Veteran Program, a massive genetic database. They also used several smaller databases. According to Yale News, researchers were able to identify dozens of genetic variants linked to cannabis use disorder and a variety of behavioral and health issues associated with cannabis use disorder.