Not everybody responds to marijuana in the same way. Some people experience anxiety after smoking while others use cannabis to treat anxiety, for example. Some develop a psychological dependence on pot while others can stop using at the drop of a hat.

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For years, scientists have tried to explain these differences, and a new study published in the Journal of Abnormal Psychology might finally have an answer: It's in your genes. A team of researchers at Washington University in St. Louis found that genetic variation in the human endocannabinoid system can greatly influence how people respond to cannabis.

Specifically, the researchers wanted to know why only some marijuana users who have experienced psychological trauma—such as childhood sexual abuse—developed a psychological dependence whereas others appeared to be immune to dependence problems. They determined that the divide was related small, genetic differences in DNA.

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The endocannabinoid system is a part of the human brain that is involved in the regulation of appetite, pain, mood, and memory. It's also the part that responds to components of cannabis such as THC. And there's apparently a single genetic variant that interacts with the system, possibly determining whether or not you are more likely to become dependent on cannabis after experiencing childhood trauma.

The researchers analyzed the genetic data of more than 15,000 Australian marijuana users and then retested the results two more times, drawing from data from earlier studies on cannabis use.

"As we expected, childhood sexual abuse was overall associated with individuals reporting a greater number of cannabis dependence symptoms, but what was particularly intriguing is that this association was only seen among people with two copies of the more common G allele," Dr. Caitlin Carey, the lead author of the study, said in a news release.

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"People with at least one copy of the less common A allele did not show this pattern, so these data suggest that the A allele may provide some form of resiliency to the development of dependence," Carey added.

While the study isn't necessarily actionable (we're quite some time away from having genetic tests for marijuana dependence, as Carey said), it does seem to open the door to future research into how genetics affect your high.