This study examined (1) whether intense and problematic social media use (SMU) were independently associated with adolescent well-being; (2) whether these associations varied by the country-level prevalence of intense and problematic SMU; and (3) whether differences in the country-level prevalence of intense and problematic SMU were related to differences in mobile Internet access. Individual-level data came from 154,981 adolescents (mean_age = 13.5) from 29 countries that participated in the 2017/2018 Health Behaviour in School-aged Children (HBSC) survey. Intense SMU was measured by the time spent on social media, whereas problematic SMU was defined by symptoms of addiction to social media. Mental (life satisfaction and psychological complaints), school (school satisfaction and perceived school pressure), and social (family support and friend support) well-being were assessed. Country-level data came from aggregated individual-level data and data from the Organisation for Economic Co-operation and Development (OECD) on Internet access. Two-level regression analyses indicated that in countries with a lower prevalence of intense SMU, intense users reported lower levels of life satisfaction and family support and more psychological complaints than nonintense users. In contrast, in countries with a higher prevalence of intense SMU, intense users reported higher levels of family support and life satisfaction than nonintense users, and similar levels of psychological complaints. In all countries, intense users reported more friend support than nonintense users. The findings regarding problematic SMU were more consistent: In all countries, problematic users reported lower well-being on all domains than nonproblematic users. Observed differences in country-level prevalence rates of intense and problematic SMU could not be explained by mobile Internet access. Adolescents reporting problematic SMU are particularly at risk of lower well-being. In many countries, intense SMU may be a normative adolescent behavior that contributes positively to specific domains of their well-being.

It is widely proven that being physically active and avoiding sedentary behaviour help to improve adolescents’ well-being and keep them in better health in general. We aimed to investigate the relationship between modes of transport to school and subjective complaints among schoolchildren. Analyses were based on the HBSC (Health Behaviour in School-aged Children) surveys conducted in 2017/18 in nine countries (N = 55,607; mean age 13.43 ± 1.64 yrs.). The main outcome showed that health complaints consisted of somatic and psychological complaints. Transport to school was characterized by mode of getting there (walking, biking, or another passive mode). A total of 46.1% of students walked and 7.3% cycled to school; 46.6% commuted by passive means. Biking to school was more frequent in Denmark (37.9%), Norway (26.5%), and Germany (26.6%). The multivariate generalized linear model adjusted for age, gender, country, and school proximity showed that biking to school is protective against reports of health complaints. The beta parameters were equal to −0.498 (p < 0.001) for the general HBSC-SCL index, −0.208 (p < 0.001) for the somatic complaint index, and −0.285 (p < 0.001) for the psychological complaints index. Young people who actively commute to school are less likely to report health complaints, especially psychological symptoms.

The objective of the paper was to investigate the association between PA and general life satisfaction in adolescents, taking into account family affluence and selected psychological, family and school factors. The survey (2015) involved 4085 Polish lower-secondary school students. Life satisfaction was measured with the abridged Students’ Life Satisfaction Scale (SLSS). Vigorous Physical Activity, self-esteem, family affluence, family relations and the perception of the school environment were considered as independent variables. Hierarchical and path models were applied. The mean SLSS score was M = 4.66 (SD = 2.23), and 36.9% of its variability was explained—mainly by self-esteem. The impact of PA on self-esteem became stronger when family affluence decreased, which led to the conclusion that material status may modify the impact of behavioural factors on the SLSS scores’ variability in adolescence.

(1) Background: The World Health Organization (WHO)-5 Well-Being Index has been used in many epidemiological studies to assess adolescent mental well-being. However, cross-country comparisons of this instrument among adolescents are scarce and, so far, no good-fitting, common invariant measurement model across countries has been reported. The present study aims to evaluate and establish a version of the WHO-5 Well-Being Index that allows for a valid cross-country comparison of adolescent self-reported mental well-being. (2) Methods: Using data from the 2018 Health Behaviour in School-aged Children study, we evaluated the measurement model and measurement invariance of the five items of the WHO-5 Well-Being Index. We used nationally representative samples of 11-, 13-, and 15-year-old adolescents (N = 74,071) from fifteen countries and regions in Europe. Measurement invariance of the WHO-5 was assessed using a series (country, gender, and age) of multi-group confirmatory factor analyses. In addition, we evaluated the convergent validity of the measure by testing its correlations with psychosomatic complaints, life satisfaction, and self-rated health. (3) Results: We found that WHO-5 does not show good psychometric properties or good measurement invariance fit. However, by excluding the first item of the scale (“I have felt cheerful and in good spirits”), the WHO-4, consisting of the other four original items, had good psychometric properties, and demonstrated good suitability for cross-national comparisons (as well as age and gender) in adolescent mental well-being. (4) Conclusions: The present study introduces the WHO-4—a revised version of the WHO-5—, that allows for a valid comparison of mental well-being across fifteen countries and regions in Europe. The WHO-4 proved to be a reliable and valid instrument to assess mental well-being in the adolescent population.

Mental health problems during adolescence are becoming increasingly frequent. The purpose of this study was to evaluate the total impact of selected behavioural and environmental factors on the variability of mental well-being indexes of young people aged 15 to 17 years. The survey, conducted as part of the last round of the Health Behaviour in School-Aged Children (HBSC) 2017/18 study, covered 3693 secondary school students in Poland at the average age of 16.53 years (SD = 1.09). Dependent variables: depression (CES-DC), stress (Cohen scale), satisfaction with life (Cantril’s Ladder), and self-efficacy in social relations (Smith and Betz scale). Independent variables included: physical activity; sedentary behaviours; length of sleep; and perception of the environment in which the respondent was raised. The analyses were adjusted by gender, age, and occurrence of chronic disease. It was demonstrated that gender, duration of sleep, and perception of the surrounding environment proved to be significant predictors of all four mental health indicators. The protective influence of physical activity appeared to be a particular advantage in a less-supportive environment. The intervention programmes aimed at improving the mental well-being of young people should include promoting physical activity and sufficient sleep; furthermore, environmental moderators should be taken into consideration.

Social media use has increased rapidly during the past decade, raising concerns about adolescents who display problematic social media use (PSMU), as indicated by addiction-like symptoms (e.g., preoccupation, tolerance). We aimed to assess the extent to which an individual resource (health literacy), and social resources (friend support and family support), moderated the association between a range of individual characteristics (gender, age, family affluence, and depressive feelings) and PSMU; also the association between PSMU and health outcomes (self-rated health, life satisfaction, and sleep difficulties), both cross-nationally and nationally. Our sample included 22,226 adolescents from six European countries. We used data from the Health Behaviour in School-aged Children cross-sectional survey (2017/2018). Random-effects models and moderator analyses were applied. Six moderations were found, with the resources moderating the association between individual characteristics and PSMU. One moderation emerged cross-nationally, namely that a higher level of family support was associated with a lower likelihood of PSMU, especially among adolescents who did not have frequent depressive feelings. In addition, five national moderations were identified. For example, a higher level of health literacy was associated with a lower likelihood of PSMU among Finnish girls. The resources were also found to moderate the association between PSMU and health outcomes, with two moderations emerging cross-nationally. For instance, a higher level of family support was related to higher self-rated health, especially among problematic users. In addition, nine national moderations were identified; these included a higher level of health literacy being associated with having less sleep difficulties, especially among problematic users in Germany. In adolescence, health literacy, family support, and friend support have the potential to moderate the association between individual characteristics and PSMU, and between PSMU and health outcomes, cross-nationally and nationally. We recommend the use of universal and targeted interventions to promote individual and social resources to counteract PSMU.