Past-Year Cough Medicine Misuse As a Predictor of Nonmedical Prescription Drug Use Among Adolescents and Young Adults

Background/Purpose: Nonmedical prescription drug use (NMPDU) has steadily increased between 2000 and 2015 and is correlated with numerous negative health and social outcomes. Although less studied, the recreational misuse of over-the-counter cough medicines, specifically those containing dextromethorphan (DXM), has also become a growing concern during this time-frame, increasing in use between 2000 and 2006 and plateauing up until 2015, the most recent trend data available. OTC cough medicines containing DXM are an easily accessed substance of abuse for all ages and has been linked with hypertension, tachycardia, psychosis, and seizures. The purpose of this study was to provide updated trends analysis with recent data, and examine correlations between NMPDU and cough medicine misuse

Methods: Data for this study came from the National Survey on Drug Use and Health (NSDUH), an annual survey of American adolescents and adults. The sample included n=68,216 adolescents and young adults, aged 12-25. A trends analysis following CDC-issued guidelines was used to examine use trends from 2015 to 2020. Next, a logistic regression model was created to examine the likelihood of having used nonmedical prescription drugs in the past year. Predictor variables included past-year cough medicine misuse, past-year marijuana use, past-month alcohol use, and past-year depressive episode, along with age (12-17 or 18-25), sex, and race.

Results: Around 51% of the sample was female, with around 53% non-Hispanic white. Around 6% of the sample had engaged in NMPDU in the past year, while 1.3% had misused cough medicine. On the bivariate level, cough medicine misuse was associated with past-year NMPDU, age, marijuana use, and alcohol use. Trends analysis found there had been no significant changes in use between 2015 and 2020 among either age group. A logistic regression model was then created to assess the likelihood of NMPDU, with past-year cough medicine misuse, past-year marijuana use, past-month alcohol use, age, sex, and race as predictors. Past-year cough medicine misuse significantly increased the likelihood of having engaged in past-year NMPDU (OR= 5.74, SE= 0.72, CI= 4.47 – 7.38, p < 0.01). Additionally, past-year marijuana use (OR= 5.33, CI= 4.81 – 5.92, p < 0.01), past-month alcohol use (OR= 1.56, CI= 1.37 – 1.79, p < 0.01), age (OR= 1.25, CI= 1.10 – 1.42, p < 0.01), and sex (OR= 1.18, CI= 1.07 – 1.30, p < 0.01) were significant predictors as well. A significant interaction effect was also observed between age and cough medicine misuse (OR= 0.54, CI= 0.35 – 0.85, p < 0.01), with past-year cough medicine misuse having a stronger predictive effect among adolescents than young adults.

Conclusions and Implications: Results from this study indicate that adolescents and young adults continue to misuse OTC cough medicine, and those who misuse cough medicine are much more likely to misuse prescription medications. This effect is stronger for adolescents than for young adults, possibly relating to legality of and access to substances of abuse. More research is needed regarding the effects of OTC cough medicine misuse on adolescent health and development.