Impact of COVID-19 pandemic on mental health and health behaviors in Swedish adolescents.

There is an urgent need to explore the impact of the COVID-19 pandemic on adolescent mental health and health behaviours. To date, there are no such studies on Swedish adolescents. As COVID-19 emerged in the middle of our ongoing 2-year follow-up examination of the Study of Adolescence Resilience and Stress, we had the unique opportunity to use the corona outbreak as a 'natural experiment' to study the impact of COVID-19 on 15-year-old adolescents in Sweden. Adolescents (baseline age 13.6±0.4 years) were recruited from schools in western Sweden (during the COVID-19 outbreak schools were kept open for those under 16 years of age). The COVID-19 pandemic reached Sweden on 31 January 2020. A total of 1316 adolescents answered the 2-year follow-up survey before (unexposed to COVID-19 pandemic, controls) and 584 after 1 February 2020 (COVID19-exposed). Data on stress, psychosomatic symptoms, happiness, relationships with parents and peers, school and health behaviours were collected. Adolescents reported higher levels of stress and psychosomatic symptoms and lower levels of happiness at follow-up compared to baseline. These changes occurred to a similar extent in both the control and COVID-19-exposed groups. Likewise, the COVID-19-exposed group showed no deterioration in peer relations or relations with parents versus controls. We did not find any significant differences between groups regarding sleep duration and physical activity.