A new study published in the journal Addiction has found a higher rate of cannabis use in states that have legalized the drug, comparing 111 pairs of twins split between states with and without legal cannabis.
“There appears to be a ~ 20% average increase in cannabis use frequency attributable to recreational legalization,” the study’s abstract stated.
The study used cohorts of twins from Colorado and Minnesota. While Colorado has legal weed and Minnesota does not, the two states are demographically similar.
“Observing differences within twin pairs provides a natural way to control potential confounding factors… twins provide extremely well-matched controls for each other,” the study’s introduction says.