ANN ARBOR—More than 17 million Americans misused prescription drugs in the past year—a behavior most common during late adolescence and young adulthood.

Now, a new University of Michigan study shows that the frequency and age at which older teens and young adults misuse prescription drugs are two predictors of substance use disorders later in life, especially alcohol misuse.

The study examined annual misuse patterns for prescription opioids, stimulants and sedatives/tranquilizers in the same individuals from age 18 to 35 to learn which prescription drug use trajectories predicted later symptoms of substance use disorders.

“We found that any misuse predicted substance-related problems, but when annual misuse peaked at 10 or more occasions the odds of developing serious substance-related problems skyrocketed,” said Sean Esteban McCabe, first author of the study, which appears in The Lancet Psychiatry.

Those odds increased with peak use age.

“More than two thirds of individuals (68.7%) who had a later peak in annual prescription drug misuse, at ages 27-28, developed two or more substance use disorder symptoms at age 35,” said McCabe, U-M professor of nursing and co-director of the Center for the Study of Drugs, Alcohol, Smoking and Health.

Of those, 55% showed symptoms of alcohol use disorder, the study found. Among those whose misuse peaked earlier, at ages 23-24, 56% showed signs of substance use disorder by age 35. Of those who rarely misused prescription drugs, about 22% showed symptoms of any substance use disorder.

“Interventions to address prescription drug misuse need to be designed to treat symptoms related to prescription drug misuse and other substance use disorders, especially symptoms of alcohol use disorder,” McCabe said. “As we show in this study, the trajectory of prescription drug misuse is important in setting the stage for adulthood substance use disorder, particularly in terms of the timing of the peak of misuse.”

Using data from the national U.S. Monitoring the Future study, the researchers identified five drug misuse trajectories: rare or no misuse and peak misuse at age 18, ages 19-20, ages 23-24 and ages 27-28.

Misuse trajectories were similar, with the exception of sedatives and tranquilizers, in which misuse peaked at an older age. This suggests that risks of prescription drug misuse span different ages and vary among drug classes, McCabe said.

Co-authors include: Philip Veliz, Kara Dickinson and John Schulenberg of U-M and Ty Schepis of Texas State University.

The NIDA-funded paper, “Trajectories of prescription drug misuse during the transition from late adolescence into adulthood in the USA: a national longitudinal multi-cohort study,” appeared online on Sept. 11.

More information:

• Study: Trajectories of prescription drug misuse during the transition from late adolescence into adulthood in the USA: a national longitudinal multi-cohort study
• Sean Esteban McCabe