The legalization of recreational marijuana in multiple states in the U.S. has increased the simultaneous use of alcohol and cannabis, a new study shows. Currently, 21 states in the U.S. have legalized the recreational use of marijuana, with Missouri being the latest to do so. Washington D.C. and Guam also have cannabis-friendly policies.

The study, which was published in the Journal of General Internal Medicine defines "simultaneous use" as "using both substances within a short time interval so that their effects overlap."

A cocktail of alcohol and marijuana may cause alcohol abuse disorders. The use of these substances also indicates impaired judgment as more than 40 percent of users said they drive when intoxicated, The Hill reported.

Simultaneous use of alcohol and marijuana "has a greater risk of potential negative consequences than single-substance use and is more common in younger age," the researchers noted.

For this study, researchers used a deep data set collected between 2008 and 2019 for the National Survey on Drug Use and Health. It included more than 817,359 participants, all of whom were reportedly older than 12 years of age.

Researchers found that simultaneous use of alcohol and marijuana saw an uptick of about 2% in people aged between 21 and 50. However, it was unchanged for individuals aged between 12 and 20.

Researcher Silvia Martins connected the simultaneous use with the increased availability of cannabis products. "The greater availability and opportunity to access cannabis through legal supply chains available for adults ages 21 and over such as dispensaries may explain why we observed increases in simultaneous cannabis/alcohol use in those aged 21–50 but not 12–20 years," Martins noted in a press release.

The study that found over 40% of Americans who consume alcohol or marijuana, or both, admitting to driving under influence was reported in February earlier this year.

A separate study published on the U.S. National Institute of Drug Abuse website also reached similar results. It says that "young adults drank more alcohol on days when they also used marijuana than on days when they only drank alcohol."

Alcohol and marijuana are two of the most common substances involved in impaired driving and motor vehicle crashes in America, according to Columbia Mailman School researcher Priscila Dib Goncalves. Nearly 70% of those who have admitted to driving under influence come from states with cannabis-friendly policies.

Representation. Marijuana. lovingimages/Pixabay