COVID-19 Pandemic Quarantines and Mental Health Among Adolescents in Norway.

Importance: Adolescence is a critical developmental phase when mental health disorders, such as anxiety and depression, often emerge. Stringent public health measures and quarantine mandates during the COVID-19 pandemic could threaten adolescent mental health.

Objective: To investigate the associations of public health measures and quarantine experiences with mental distress among Norwegian adolescents and to explore if certain vulnerability factors moderate these associations.

Design, Setting, And Participants: This longitudinal cohort study used repeated measures to capture variations in mental distress explained by the stringency of public health measures and quarantine experiences. Data from the Norwegian Mother, Father, and Child cohort study were linked to national health registries and a national stringency index from April 1, 2020, to February 17, 2021. Participant included 7787 Norwegian adolescents aged 16 to 18 years. Data were analyzed from October 2022 to October 2023.

Exposures: Stringency index of public health measures and quarantine experiences including recent quarantine (within the last 2 weeks) and quarantine frequency (cumulative number of quarantine episodes).

Main Outcome And Measures: Mental distress was measured using the Hopkins Symptom Checklist across 6 data collection waves.

Results: In this study, 7787 participants were included in the analysis (4473 female [57%]; mean [SD] age, 17.0 [0.6] years). Stringent public health measures (β = 0.18; SE, 0.02; P < .001), recent quarantine (β = 0.11; SE, 0.02; P < .001), and frequent quarantine (β = 0.08; SE, 0.01; P < .001) were associated with higher levels of mental distress. The associations between public health measures and mental distress were not moderated by sex, age, prepandemic anxiety or depression, or genetic liability for mental health conditions. Frequency of quarantine appeared to be more strongly associated with mental distress among younger adolescents (β = -0.04; SE, 0.01; P = .008), those with parents with lower education (β = -0.04; SE, 0.01; P = .007), and those with lower genetic risk for depression (β = -0.03; SE, 0.01; P = .006).

Conclusions And Relevance: In this study, younger adolescents, those with parents with lower education, or those with low genetic liability for depression appeared more vulnerable when being quarantined several times. These findings emphasize the need for targeted support strategies to better protect adolescent well-being during future crises. Adolescents who experienced increased mental distress during the COVID-19 pandemic may be at risk of continued mental health problems and in need of ongoing support.