Is fatigue associated with adolescents' mental health? A pre- vs. post-COVID-19 cross-sectional survey comparison

Fatigue is a common complaint reported by adolescents and adults; and one of the persistent symptoms of long COVID-19. The aim of this study was to assess the prevalence of self-reported fatigue and associated factors among adolescents in Finland at two distinct time points, pre- (2018) and post-COVID (2023).

A cross-sectional survey was conducted among adolescents in two cities, Rovaniemi and Salo, Finland, in 2018 and 2023. All schools with students in the 7-9th grades in Rovaniemi (10) and Salo (4) cities were invited to participate in the survey, except special needs schools and classes. The Checklist Individual Strength (CIS) questionnaire was used to determine the severity of fatigue among adolescents. A total of 5,583 adolescents aged 13-17 years (n = 2,774, in 2018) and (n = 2,809, in 2023) were included in the analyses. Linear regression analysis was used to determine the association between fatigue, survey year and explanatory variables.

The prevalence of fatigue increased among females from 16.2% in 2018 to 24.3% in 2023 (p < 0.001), but not among males at 6.7% vs. 5.6% (p = 0.239) respectively. The mean fatigue score change among females was 29.1 vs. 32.2 (p < 0.001), and males 24.6 vs. 25.2 (p = 0.081) in 2018 vs. 2023 respectively. The fatigue score was higher among females by 0.7 points in 2023 (β = 0.68; 95% CI: 0.07, 1.28), but not among males (β = 0.03; 95% CI: -0.56, 0.62). Internalizing problems were associated with fatigue among females (β = 5.00; 95% CI: 4.68, 5.32); and males (β = 3.74; 95% CI: 3.37, 4.11). Externalizing problems were associated with fatigue (β = 2.87; 95% CI: 2.53, 3.20) among females and (β = 2.19; 95% CI: 1.85, 2.53) males. Other factors associated with fatigue included living with one biological parent and being overweight among across both sexes.

The notable increase in fatigue, among girls, post-COVID highlights the need for sustained attention to adolescent mental health and physical health, especially in relation to internalizing and externalizing problems.