Marijuana use disorder is common in the U.S.; is often associated with other substance use disorders, behavioral problems, and disability; and goes largely untreated, according to a new study conducted by the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of the National Institutes of Health. The analysis found that 2.5% of adults––nearly 6 million people—experienced marijuana use disorder during the past year, while 6.3% had met the diagnostic criteria for the disorder at some point in their lives.
The new study, published online in the American Journal of Psychiatry, analyzed data about marijuana use that were collected in the 2012–2013 wave of the NIAAA’s National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), the largest study ever conducted on the co-occurrence of alcohol use, drug use, and related psychiatric conditions.
The researchers interviewed more than 36,000 U.S. adults about their alcohol use, drug use, and related psychiatric conditions. Notably, the investigators applied diagnostic criteria for marijuana use disorder from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), to the NESARC data. In DSM-5, marijuana dependence and abuse are combined into a single disorder. To be diagnosed with the disorder, individuals must meet at least two of 11 symptoms that assess craving, withdrawal, lack of control, and negative effects on personal and professional responsibilities. The severity of the disorder is rated as mild, moderate, or severe depending on the number of symptoms met.
Consistent with previous findings, the new data showed that marijuana use disorder is about twice as common among men than women, and that younger age groups are much more likely to experience the disorder than are people 45 years of age and older. The risk for onset of the disorder was found to peak during late adolescence and among people in their early 20s, with remission occurring within three to four years. The new study also found that past-year and lifetime marijuana use disorders were strongly and consistently associated with other substance use and mental health disorders.
The researchers reported that people with marijuana use disorder, particularly those with severe forms of the disorder, experience considerable mental disability. They noted that previous studies have found that such disabilities persist even after the remission of marijuana use disorder. The investigators also reported that only about 7% of people with past-year marijuana use disorder received marijuana-specific treatment compared with slightly less than 14% of people with lifetime marijuana use disorder.
“These findings demonstrate that people with marijuana use disorder are vulnerable to other mental health disorders,” said Nora D. Volkow, MD, director of the National Institute on Drug Abuse (NIDA), which contributed funding to the investigation. “The study emphasizes the need for such individuals to receive help through evidence-based treatments that address these co-occurring conditions.”
Source: NIH; March 4, 2016.