Amid changing attitudes and new legislation around the use of cannabis in the US, an increasing number of people are taking the drug on a regular basis.

Recent estimates based on survey results suggest use of the drug had risen steadily across a range of demographics, with one curious exception – teenagers.

According to the data analyzed by researchers from the University of Kentucky and the University of Louisville, cannabis use in higher-income households (earning $75,000 a year or more) and by those with college degrees has more than doubled, while among individuals aged 12 to 17 prevalence has remained unchanged.

The study is based on data provided by 543,195 people collected between 2013 and 2022 as part of the National Survey on Drug Use and Health. Participants aged from 12 years and up were quizzed on their cannabis use in the previous 30 days.

“Cannabis use is increasing due to several factors including the adoption of laws legalizing its use across the United States,” write the researchers in their published paper.

While cannabis use hasn’t gone up for those aged 12 to 17 years old, over the whole study sample it’s risen from 7.59 percent to 15.11 percent in the 9 years studied. There was no significant rise in 2020, likely due to the impact of the coronavirus pandemic and changes to the method of data collection in that period.

Though the survey’s results can’t confirm driving factors behind the change, the trend aligns with the growing legalization of the drug for recreational use. In 2012, two states, Colorado and Washington, made recreational use legal in a national first. As of today, cannabis is legal in 38 out of 50 states for medical use, and 24 states for recreational use.

“Future research examining influences on cannabis use, such as recreational and medical legalization, psychiatric comorbidity trends including anxiety and depression, and cannabis-related social acceptability and perceptions of harm, is imperative,” write the researchers.

Cannabis remains the most-used psychoactive substance in the US, with 61.9 million people – some 22 percent of the population – reporting cannabis use in the past year (whereas this study looked at the past 30 days).

We’re still learning about some of the potentially negative ways in which the drug might affect the brain and body, including increasing the frequency of psychotic episodes, and potentially raising the risk of cancer. The researchers want to see further studies done on the health impacts of cannabis as the drug continues to get more popular.

“Our findings inform prevention and harm reduction efforts aimed at mitigating the prevalence of cannabis use in the US,” write the researchers.

The research has been published in Drug and Alcohol Dependence Reports.