Effect of the COVID-19 pandemic on adolescent mental health and substance use up to March, 2022, in Iceland: a repeated, cross-sectional, population-based study.

BACKGROUND: Poor mental health in the first year of the COVID-19 pandemic has been well documented in adolescents; however, less is known about the longer-term effect of the pandemic. We aimed to examine adolescent mental health and substance use as well as covariates associated with these outcomes 1 year or more into the pandemic. METHODS: A nationwide sample of adolescents aged 13-18 years enrolled in school in Iceland were invited to complete surveys administered during October-November or February-March, 2018, October-November, 2020, February-March or October-November, 2021, and February-March 2022. The survey was in Icelandic for all administrations and offered to adolescents aged 13-15 years in English in 2020 and 2022 and in Polish in 2022. Surveys assessed depressive symptoms (Symptom Checklist-90); mental wellbeing (Short Warwick Edinburgh Mental Wellbeing Scale); and the frequency of cigarette smoking, e-cigarette use, and alcohol intoxication. Covariates comprised age, gender, and migration status as determined by language spoken at home, level of social restrictions based on residency, parental social support, and sleep duration (≥8 h nightly). Weighted mixed-effect models were used to determine the effect of time and the covariates on mental health and substance use. The main outcomes were assessed in all participants with more than 80% of the necessary data, and multiple imputation was used to handle missing data. Bonferroni corrections were used to adjust for multiple testing and analyses were considered significant at a p value of <0·0017. FINDINGS: 64 071 responses were submitted and analysed between 2018 and 2022. Elevated depressive symptoms and worsened mental wellbeing across girls and boys aged 13-18 years were observed to have been maintained up to 2 years into the pandemic (p>0·0017). Alcohol intoxication initially decreased during the pandemic but increased again as social restrictions eased (p<0·0001). No changes were observed in cigarette smoking and e-cigarette use during the COVID-19 pandemic. Higher levels of parental social support and an average sleep duration of 8 h or more per night were associated with mental health better outcomes and less substance use (p<0·0001). Social restrictions and migration background were inconsistently associated with the outcomes. INTERPRETATION: Population-level prevention targeting adolescent depressive symptoms should be prioritised in health policy in the wake of COVID-19. FUNDING: Icelandic Research Fund.

Depressive symptoms, mental wellbeing, and substance use among adolescents before and during the COVID-19 pandemic in Iceland: a longitudinal, population-based study.

BACKGROUND: Adolescence represents a crucial developmental period in shaping mental health trajectories. In this study, we investigated the effect of the COVID-19 pandemic on mental health and substance use during this sensitive developmental stage. METHODS: In this longitudinal, population-based study, surveys were administered to a nationwide sample of 13-18-year-olds in Iceland in October or February in 2016 and 2018, and in October, 2020 (during the COVID-19 pandemic). The surveys assessed depressive symptoms with the Symptom Checklist-90, mental wellbeing with the Short Warwick Edinburgh Mental Wellbeing Scale, and the frequency of cigarette smoking, e-cigarette use, and alcohol intoxication. Demographic data were collected, which included language spoken at home although not ethnicity data. We used mixed effects models to study the effect of gender, age, and survey year on trends in mental health outcomes. FINDINGS: 59 701 survey responses were included; response rates ranged from 63% to 86%. An increase in depressive symptoms (ß 0·57, 95% CI 0·53 to 0·60) and worsened mental wellbeing (ß -0·46, 95% CI -0·49 to -0·42) were observed across all age groups during the pandemic compared with same-aged peers before COVID-19. These outcomes were significantly worse in adolescent girls compared with boys (ß 4·16, 95% CI 4·05 to 4·28, and ß -1·13, 95% CI -1·23 to -1·03, respectively). Cigarette smoking (OR 2·61, 95% CI 2·59 to 2·66), e-cigarette use (OR 2·61, 95% CI 2·59 to 2·64), and alcohol intoxication (OR 2·59, 95% CI 2·56 to 2·64) declined among 15-18-year-olds during COVID-19, with no similar gender differences. INTERPRETATION: Our results suggest that COVID-19 has significantly impaired adolescent mental health. However, the decrease observed in substance use during the pandemic might be an unintended benefit of isolation, and might serve as a protective factor against future substance use disorders and dependence. Population-level prevention efforts, especially for girls, are warranted. FUNDING: Icelandic Research Fund. TRANSLATION: For the Icelandic translation of the abstract see Supplementary Materials section.