Background: Self-efficacy has been identified as an important health-promoting factor for both physical and mental health. Previous studies have examined self-efficacy as a moderating factor between negative psychosocial influences and various outcomes, e.g., life satisfaction and stressors. There is, however, limited knowledge about factors that strengthen self-efficacy. The aim of this study is to examine the association between mastery experiences, social support, and self-efficacy among adolescents in secondary schools in Norway. Methods: This study is based on cross-sectional data from the Ungdata surveys conducted in eastern part of Norway in 2021. The sample comprises 9,221 adolescents aged 13–16. Sequential multivariate linear regression was conducted to explore the association between mastery experiences, social support, and self-efficacy. Results: The final model (Model 3) explains 25% of the total variance in self-efficacy. The indicators concerning mastery experiences – defined here as the personal experience of success – explain more of the observed variance in self-efficacy than the other independent variables (change in R square = 10.7%). The items ‘felt mastering things’ ‘and ‘felt useful’ make the strongest and most significant contributions to the variance in self-efficacy in the final model (β = 0.25, p < 0.001 and β = 0.16, p < 0.001, respectively), followed by the variables ‘support from friends’ and ‘parental support’ (β = 0.06, p < 0.001 an β = 0.06, p < 0.001). Conclusions: Mastery experiences are potential sources for creating and strengthening self-efficacy. Awareness of the health-promoting potential in (strengthening) self-efficacy among adolescents is important. Additional research is needed to further explore these associations.

The purpose was to analyse the association between physical activity taking place in different contexts (sports club, gym, exercise independently and other organized physical activities) and symptoms of depression. The study was based on self-reported cross-sectional data from the Ungdata survey, conducted in 2017 by the Norwegian Social Research (NOVA) institute in cooperation with regional centres for drug rehabilitation. The target group comprised 5531 15–16 years old adolescents (Grade 10 students) and 11,655 students in grades 8 and 9 in Norway. Based on Rasch analysis, six items on depressions symptoms were used to create a composite measure of depression. Binomial logistic regression was used to analyse the association between physical activities in different contexts and symptoms of depression. In the crude model, the odds for symptoms of depression were lower for those who were physically active in a sports club (OR: 0.40, 95% CI: 0.30–0.53), in a sports club and gym (OR: 0.40, 95% CI: 0.28–0.56), in a sports club and exercise or keep fit independently (OR: 0.52, 95% CI: 0.38–0.72) and in a sports club, gym and exercise or keep fit independently (OR: 0.58, 95% CI: 0.41–0.81). After adjustment for potential confounders, the association became significant only for those who were physically active in a sports club (OR: 0.57, 95% CI: 0.40–0.81) and other organized physical activities, e.g. dance, martial arts (OR: 0.52, 95% CI: 0.31–0.86). Analysis for grade 8 and 9 showed the same patterns for the associations between sports club and symptoms of depression (grade 8: crude model, OR: 0.47, adjusted model, OR: 0.63, grade 9: crude model, OR: 0.44, adjusted model, OR: 0.49). Physical activity in a sports club was associated with significantly lower odds for symptoms of depression, suggesting a possible role for social interaction in addition to physical activity per se. It is important, therefore, to consider in which types of contexts physical activities take place, not only focusing on physical activity frequency and volume when investigating the association between adolescents’ physical activity and mental health. Additional research is needed to further explore these associations as well as measures of physical activity and mental health.

Background: Mental health problems have increased noticeably among adolescents. Physical activity has been identified as an important factor in the promotion of mental health. The purpose of this study was to explore how leisure time physical activity was associated with depressive symptoms among adolescents in Sweden. Methods: Using binary logistic regression we analyzed Swedish data collected as part of the Children of Immigrants: Longitudinal Survey in Four European Countries. The complete sample used for analysis consisted of 3787 adolescents (including 1855 boys and 1932 girls). Results: Adolescents who participated in physical activity during their leisure time on a daily, weekly, or monthly basis had substantially lower odds of often feeling depressed than those who were physically inactive. This pattern applied to both boys and girls. Relative to boys, girls had significantly higher odds of often feeling depressed. Conclusions: The findings of this study suggested that participation in physical activity regularly during leisure time was associated with a lower level of depressive symptoms among adolescents in Sweden. Because of the cross-sectional study design conclusions about causality cannot be drawn. Future research based on longitudinal data is needed to further explore the mechanisms behind the association. This study calls for recognition of the value of physical activity in promoting mental health among adolescents.

Background: Scales measuring depressive symptoms in adolescents and adults are widely used for epidemiological purposes. The purpose of this study is to use Rasch measurement theory to examine the psychometric properties of a six-item scale intended to measure depressive symptoms in Norwegian adolescents. Methods: The study is based on cross-sectional data from Ungdata, a survey conducted by the Norwegian Social Research Institute in cooperation with Regional Centres for Drug Rehabilitation in 2017. The target group comprised 13- to 19-years olds in Norway. Six items with four response categories, intended to measure depressive symptoms, were analysed. The analysis focused on invariance, including differential item functioning across gender and school levels. In addition, targeting, possible multidimensionality, response dependency, and the categorisation of the items were analysed. Results: The scale measuring depressive symptoms shows good reliability and, on the whole, the items work well. However, one item, ‘had sleep problems’, clearly misfit and another, ‘worried too much about things’, works differently for males and females. Conclusions: The scale has the potential to measure depressive symptoms in adolescents though there is room for improvement. To further improve the scale, the item concerning sleep problems should be rephrased.

Aims: The aim of this work was to examine psychological distress among Norwegian adolescents in relation to changes over time and the associations with leisure time physical activity and screen-based sedentary behaviour. Methods: This cross-sectional study was based on data retrieved from the Norwegian Youth Health Surveys in 2001 and 2009 in Hedmark County. Adolescents aged 15–16 years old completed a questionnaire regarding physical activity, sedentary behaviour, psychological distress and other health and lifestyle variables. The self-report Hopkins Symptom Checklist-10 was used to assess psychological distress. Multinomial logistic regression was used to analyse the associations between psychological distress, physical activity and sedentary behaviour. Results: Self-reported psychological distress increased significantly from 2001 to 2009 (from 19.4 to 28.2%), with the proportion of girls reporting psychological distress being twice as large as the proportion of boys. The proportion of adolescents who were physically active for ⩾11 hours per week increased significantly over the same period (from 6.0 to 10.4%). Sedentary behaviour ⩾6 hours per school day increased significantly among both sexes between 2001 and 2009. Physical activity (⩾11 hours) and sedentary behaviour (⩾6 hours) were both significantly associated with psychological distress. Conclusions: The association between physical activity, sedentary behaviour and psychological distress was weak; only high amounts of physical activity and high amounts of screen-based sedentary behaviour were associated with psychological distress. Longitudinal studies are needed to provide further insights into these associations and to understand the extent to which these variables might be causally related.

Background: This study’s purpose was to examine the association between a broad range of lifestyle habits and depressive symptoms in Norwegian adolescents. Methods: This study was based on national, self-reported, cross-sectional data from the Ungdata Surveys, conducted in 2017–2019. The target group comprised 244,250 adolescents (ages 13–19). Binominal logistic regression was used to analyse the association between lifestyle habits (physical activity, social media use, gaming, dietary habits, smoking, smokeless tobacco, alcohol intoxication) and depressive symptoms. The outcome measure was defined as a high level of depressive symptoms (≥80th percentile). Separate analyses were performed for boys and girls, and all models were adjusted for perceived family economy, parental higher education and age. Results: The odds of having depressive symptoms were significantly lower among those who reported being physically active at least 3 times per week (OR; boys: 0.81, girls: 0.83), used social media ≤3 h per day (OR; boys: 0.65, girls: 0.70), engaged in gaming ≤3 h per day (OR; boys: 0.72, girls: 0.77), were non-smokers (OR; boys: 0.74, girls: 0.72) and had not experienced alcohol intoxication during the previous 12 months (OR; boys: 0.66, girls: 0.67). Furthermore, the results indicated a significant inverse association between depressive symptoms and high consumption of a range of healthy food items and low consumption of unhealthy food and beverages among girls. Similar tendencies were found among boys (OR; 0.77–0.91). Finally, higher adherence to healthy lifestyle habits was associated significantly with lower odds of having depressive symptoms among both genders (OR; boys: 0.40, girls: 0.52). Conclusions: A healthier lifestyle was associated with lower odds of having depressive symptoms. Additional research is needed to confirm a possible causal relationship.