Currently marijuana use has become legal in a number of states in the US, and more people use the drug without knowing the disorders it can cause.
This is reported by a recent study published in The Lancet Psychiatry.
Researchers from National Institutes of Health, Substance Abuse and Mental Health Services Administration and US Department of Health and Human Services analyzed several annual national US surveys.
A total of 569,500 adults participated in these surveys. All people were US civilians aged 18 years or older who participated in annual, cross-sectional US National Surveys on Drug Use and Health from 2002 to 2014.
The sample in each US state was designed to be approximately equally distributed between participants aged 12–17 years, 18–25 years, and 26 years or older.
For each survey year, researchers estimated prevalence of marijuana use and use disorders, initiation of marijuana use, daily or near daily use, perception of great or no risk of harm from smoking marijuana, perception of state legalization of medical marijuana use, and mean number of days of marijuana use in the previous year.
Researchers found that marijuana use increased from 10.4% to 13.3% in adults from 2002 to 2014. In addition, the prevalence of perceiving great risk of harm from smoking marijuana once or twice a week decreased from 50.4% to 33.3%.
Changes in marijuana use and risk perception generally began in 2006–2007. In addition, decrease in risk perceptions was associated with increase in prevalence of marijuana use. However, marijuana use disorders in adults remained stable at about 1·5% between 2002 and 2014.
Researchers suggest that prevalence and frequency of marijuana use increased in adults in the USA starting in approximately 2007.
The associations between increases in marijuana use and decreases in perceiving great risk of harm from smoking marijuana require education about the risk of smoking marijuana and prevention messages.
* Marijuana use disorder is the continued use of marijuana despite clinically significant distress or impairment.
It often includes a strong desire to take the drug, difficulties in controlling its use, persisting in its use despite harmful consequences, a higher priority given to drug use than to other activities and obligations, increased tolerance, and sometimes a physical withdrawal state.