Aims: This study aimed to examine and compare the use of energy drinks, over-the-counter (OTC) painkillers and misuse of prescription drugs in two cohorts of Norwegian adolescents entering high school (i.e. grade 11) immediately prior to and during the initial year of the COVID-19 pandemic. Methods: Accelerated longitudinal design and multi-cohort sampling enabled identification of the two socio-demographically comparable cohorts of grade 11 students: (a) COVID-19 cohort assessed in the autumn of 2020 ( n=915) and (b) pre-COVID-19 cohort assessed in the autumn of 2018/19 ( n=1621). Unadjusted and adjusted logistic and Poisson models were used to estimate the proportion of (mis)users and use frequencies among (mis)users in two cohorts. Results: Energy drinks use was both more common in the COVID-19 cohort (60.8% vs. 52.5%; adjusted odds ratio=1.40, 95% confidence interval (CI) 1.18–1.66, p<0.001) and more frequent among users from this cohort than among their pre-COVID-19 counterparts (9.58 vs. 7.79 days past month, adjusted incidence risk ratio (aIRR)=1.23, 95% CI 1.14–1.32, p<0.001). No cohort differences were observed in OTC painkillers use. Prescription drugs misuse was equally common in the two cohorts but was more frequent among misusers from the COVID-19 cohort than among their pre-COVID-19 counterparts (18.94 vs. 12.45 times past year, aIRR=1.52, 95% CI 1.10–2.10, p<0.001). Conclusions: Norwegian adolescents from the COVID-19 cohort were more likely to use energy drinks and, once engaged in these behaviours, to use energy drinks and misuse prescription drugs more frequently than their pre-COVID-19 counterparts.