Kaiser Permanente researchers in Washington analyzed information from medical visits, keeping private the information that could help identify any of the 22,000 patients in the study. Published in the Journal of the American Board of Family Medicine, “Frequency of Cannabis Use among Primary Care Patients in Washington State” is among the first U.S. studies to evaluate the population-based prevalence of patient-reported cannabis use among primary care patients, particularly in a state where nonmedical use is legal.
After alcohol and tobacco, marijuana is the most commonly used drug in the United States. In recent years, the concentration of tetrahydrocannabinol (known as THC), the main psychoactive and addictive component, has increased in cannabis plants from 3 percent to 12 percent, Dr. Lapham says. And new products — like concentrated hash oil and synthetic cannabinoids — are raising the potency and risk for addiction.
About 1 in 7 adult primary care patients visiting medical offices reported having used marijuana at least once in the past year, according to a study conducted by Kaiser Permanente researchers since Washington state legalized nonmedical cannabis use in 2014.
In young adults, that rate was higher: nearly 2 in 5. Young adults — especially men age 18-29 who had depression or used tobacco — were also much more likely than others to use cannabis every day. These findings raise concerns, according to first author Gwen T. Lapham, PhD, MPH, MSW, a Kaiser Permanente Washington Health Research Institute research associate. “Much remains to be learned about marijuana use, while legalization is spreading.”