Adolescent Substance Use Among High School Students Before and After the COVID-19 Pandemic: A Repeated Cross-Sectional Study of Peer Exposure and Risk.

BACKGROUND

The COVID-19 pandemic disrupted schooling for many during the middle-to-high school transition, a critical period for initiation of substance use. This study examines how reduced in-school peer exposure was associated with substance use patterns among ninth and tenth graders before and after the pandemic.

OBJECTIVES

To examine the relationship between differential in-school peer exposure to substance use patterns among ninth and tenth graders before and after the pandemic.

METHODS

We conducted a repeated cross-sectional study of ninth and tenth graders (total N = 2,024) from a large US high school, using annual in-school survey data from 2017-2019 (N = 1,550) and 2023 (N = 474). We compared substance use prevalence and risk factors pre- and post-pandemic.

RESULTS

The pre-pandemic sample was 48% boys and the post-pandemic sample was 57% boys. Ninth graders (one year less exposure to in-school peers) had significant declines pre- to post-pandemic in 30-day alcohol use (13% to 7%), 30-day e-cigarette use (12% to 7%), lifetime alcohol use (31% to 20%), lifetime marijuana use (18% to 10%), and lifetime e-cigarette use(23% to 13%). Tenth graders (one additional year of in-school peer exposure) did not experience similar declines. Perceived substance use accessibility increased among ninth graders pre- to post-pandemic (mean risk perception score: 3.18 to 3.33, p < 0.05).

CONCLUSIONS

Less in-school peer exposure during a critical developmental period was associated with reduced substance use initiation and progression. These findings highlight the importance of in-school exposure to peers in adolescent substance use trajectories. Future research should investigate specific mechanisms of peer influence-such as substance availability on campus-to inform targeted prevention and early intervention strategies.