To Örebro University

Introduction: The COVID-19 pandemic has seen a rise in emotional problems among adolescents. Improving young people's mental health is a public health priority, and examining protective factors throughout the pandemic can offer insights on targets for prevention. This study aimed to investigate longitudinal trajectories of depressive and anxiety symptoms among a large sample of Australian adolescents and to examine sleep patterns in high- and low-risk trajectories.

Methods: This study utilises data from the control group of the “Health4Life” cluster RCT. We used three waves of questionnaire data collected annually (from 2019) from Year 7 students at 71 secondary schools across New South Wales, Queensland and Western Australia (N = 2,781, Mage = 12.6, SD = .51; 47% boys and 1.4% ‘prefer not to say’). Adolescents reported on their mental health (i.e., depressive and anxiety symptoms) and sleep (i.e., sleepiness, weekday sleep duration, SOL, WASO, and chronotype).

Results: We found four trajectories of depressive symptoms: low-stable (64.3%), average-increasing (19.2%), high-decreasing (7.1%), moderate-increasing (9.4%), and three anxiety symptom trajectories: low-stable (74.8%), average-increasing (11.6%), high-decreasing (13.6%). Adolescents in low-risk trajectories were more likely to be boys and to report shorter SOL and WASO, longer sleep duration, less sleepiness, and earlier chronotype. Where mental health waxed and waned, sleep patterns changed in the same direction.

Discussion: This is the first study to thoroughly examine adolescents’ sleep patterns as a protective factor for the development of emotional problems during the pandemic. Healthy sleep was clearly linked to low-risk trajectories, although this association is likely bi-directional.