New research is showing many of the same genetic factors that lead people to drink alcohol may lead them to smoke pot as well. While marijuana is the most heavily used illegal drug in the U.S., little is known about the genes that influence its use.
Researchers conducted interviews of nearly 3000 identical and fraternal twins ranging in age from their mid-20’s to their mid-30’s about their alcohol drinking and pot smoking activities.
Lead researcher Dr. Carolyn Sartor, PhD comments “We wanted to know if the same genes that affect risk for alcohol dependence also affect risk for marijuana dependence.”
Based on responses from the interviewees, researchers concluded 60% of the variance between alcohol abuse and/or marijuana abuse could be linked to genes.
“We found considerable overlap between the genes that contribute to marijuana dependencies and alcohol use and dependence,” Sartor says.
According to a prior study, between 8 and 12 percent of marijuana users fit the definition of dependence, meaning they continue use of the drug despite interference with family, work and school. Prior studies also show between 50 and 60 percent of the variance of alcohol abuse comes from genetics.
Findings from this newest study support the idea that a common set of genes plays a role in the abuse of any drug.