More than one in eight US adults (12.6%) used benzodiazepines in the past year, up from previous reports. Misuse of the prescription drugs accounted for more than 17% of overall use, according to a study published online today in Psychiatric Services in Advance. The researchers defined misuse as any way a doctor did not direct, including using the drug without a prescription or more often or longer than prescribed. Misuse was highest among young adults 18 to 25 (5.6%) and was as common as prescribed use.

Benzodiazepines are a class of medications used to treat conditions such as anxiety and insomnia. They include alprazolam (Xanax, Niravam) diazepam (Valium), clonazepam (Klonopin), lorazepam (Ativan) and others. Researchers analyzed data from the 2015 and 2016 National Survey on Drug Use and Health.

Although there were differences in the studies, research from 2013 and 2014 found about 4% to 6% of adults used benzodiazepines. Previous national estimates of use have not accounted for misuse. In addition to finding that overall use has increased, today’s study is the first analysis to find the highest benzodiazepine use among adults 50 to 64 years (13%); previous studies found the highest use was among those 65 and older. Whereas women were more likely than men to report any use of benzodiazepines, men were more likely than women to report misuse. Benzodiazepine use has come under increasing scrutiny given the associated harms and safer alternatives, particularly in light of the opioid epidemic. The study found benzodiazepine misuse was strongly associated with misuse of or dependence on prescription opioids or stimulants.

When asked about the reasons for misuse, nearly half said to relax or relieve tension and just over a quarter said to help with sleep. Among people taking benzodiazepines without a prescription, the most common source was a friend or relative.

The authors, led by Donovan Maust, MD, with the University of Michigan, Ann Arbor, suggest that patients also prescribed stimulants or opioids should be monitored for benzodiazepine misuse. They also note that some misuse may reflect limited access to health care generally and behavioral treatments specifically and suggest that some misuse could be reduced with improved access to behavioral interventions for sleep or anxiety.

The research was supported by a grant from the National Institute on Drug Abuse