Polysubstance use in young adults—are there predictable patterns?
In a Lancet Psychiatry commentary, Drs. Morgan M. Philbin and Pia M. Mauro, assistant professors at Columbia University Mailman School of Public Health, offer their insights on the non-medical use of prescription drugs among U.S. young adults, and specifically on a study published by a team of researchers at the University of Michigan. The Michigan investigators, led by Dr. Sean McCabe, explored patterns and drivers of young adults' non-medical use of prescription drugs— including prescription sedatives, opioids, or stimulants—and their association with substance use disorder symptoms at age 35. These trajectories of prescription drug use were based on age of peak use and ranged from "rare misuse", the most prevalent trajectory, to peak use at age 27-28, which was most strongly associated with substance use disorder symptoms at age 35.
Compared to other age groups, young adults in the United States (aged 18-25 years) report the highest prevalence of non-medical use of prescription drugs in the past year (15 percent), binge drinking in the past month (37 percent), or illicit drug use in the past month (24 percent).
"Based on the high rates of polysubstance use that we are seeing across the U.S. there is an urgency to educate youth and young adults about potential consequences associated with the non-medical use of prescription drugs. In addition, it's important to discuss diversion, or the sharing of medications with peers," according to Philbin, Ph.D., in the Department of Sociomedical Sciences.
"There were differences in peak ages for use of opioids (29-30 years), compared to sedatives (35 years), and stimulants (27-28 years). This means that the aggregated peak of 27-28 years for any non-medical use of prescription drugs is not the absolute peak for all prescription drugs," discussed Mauro, Ph.D., assistant professor of Epidemiology. "A life course perspective could help disentangle polysubstance use patterns across different developmental periods," added Mauro.
Given the differences in age of peak use across substances—for example, younger ages for stimulants than for opioids and even later for sedatives or tranquilizers—Philbin and Mauro highlight the need to incorporate polysubstance use screening and care linkage across the life course. "While methods remain challenging for adequately measuring the use of more than one substance, there are approaches one can take to more accurately understand patterns of use," they write.
While interventions play an important role in addressing polysubstance use among youth; language and terminology also matter. "For example, the ways that we, as researchers, describe substance use can directly influence perceptions about people who use drugs, and by extension impact access to screening and treatment, and the quality of medical encounters," said Philbin. "We should strive to disseminate research findings to the public in a way that increases clarity and reduces stigma. For example, using the term "non-medical substance use" instead of "misuse" can make a difference."
Mauro and Philbin's own research indicates that more than a third of young adults who use substances are not asked about illicit substance use by their providers. The measurement of polysubstance use and its consequences should incorporate also alcohol, observed Mauro and Philbin, a point also highlighted by Sean McCabe and colleagues at the University of Michigan.
"In summary, we believe in the importance of a multilevel intervention approach to minimize potential harms related to polysubstance use throughout the life course," said Philbin and Mauro. "At the individual level, health-care providers should screen patients and discuss clinically indicated treatment options. At the structural level, we feel that programs should expand access to medication, medication disposal, and harm reduction services, and ensure affordable and non-stigmatizing treatment."