The study aimed to investigate the associations between different levels of depression with different aspects of school performance. The target population included 2516 7th–9th grade pupils (13–17 years) of whom 90% completed the questionnaire anonymously in the classroom. Of the girls 18.4% and of the boys 11.1% were classified as being depressed (R‐Beck Depression Inventory (BDI), the Finnish version of the 13‐item BDI). The lower the self‐reported grade point average (GPA) or the more the GPA had declined from the previous term, the more commonly the adolescents were depressed. Depression was associated with difficulties in concentration, social relationships, self‐reliant school performance and reading and writing as well as perceiving schoolwork as highly loading. The school performance variables had similar associations with depression among both sexes when a wide range of depression was studied but gender differences appeared when studying the severe end of the depression scale. Our study indicates that pupils reporting difficulties in academic performance should be screened for depression.

The main objective was to analyse whether involvement in bullying at school predicts depression, and whether depression predicts involvement in bullying in middle adolescence. A total of 2,070 15-year-old girls and boys in two Finnish cities were surveyed at ninth grade (age 15) at schools, and followed up 2 years later in the Adolescent Mental Health Cohort Study (AMHC). Depression was measured by a Finnish modification of the 13-item short Beck Depression Inventory. Involvement in bullying was elicited by three questions focusing on being a bully, being a victim to bullying, and being left alone by peers against one's wishes. Similar questions were posed at both time points. Statistical analyses were carried out using cross-tabulations with chi-square/Fisher's Exact Test statistics, and logistic regression. The results summarized that, both being a victim to bullying and being a bully predicted later depression among boys. Among girls, depression at T1 predicted victimisation at T2. Depression at T1 predicted experience of being left alone at T2 among both sexes. It was concluded that victimisation to bullying may be a traumatising event that results in depression. However, depression also predicts experience of victimisation and of being left alone against one's wishes. Depression may impair an adolescent's social skills and self-esteem so that the adolescent becomes victimised by peers. However, depression may also distort and adolescent's experiences of social interactions.

Earlier research has associated early puberty with emotional and behavioral symptoms particularly among girls, while among boys, findings have been contradictory as to whether risks are associated with early or late pubertal timing. We studied the association between pubertal timing and substance use behaviors in middle adolescence in a 2-year follow up study of 2,070 (mean age 15.5 years, SD 0.36; 56.4% females) Finnish adolescents. Pubertal timing was measured by age at menarche/oigarche. Eleven years or less was classified as early, 12-13 years as normative and 14 years or later as late pubertal timing. Substance use behaviors were elicited by a number of questions related to alcohol use patterns, smoking and cannabis use. As factors that could explain the association between pubertal timing and substance use, we studied depressive symptoms, delinquency and aggression, and parental monitoring. In boys, all these substance use behaviors were the more common the earlier the puberty and the associations persisted at age 17. Among girls, early pubertal timing was similarly associated with substance use behaviors at age 15, but no longer at age 17. The associations between pubertal timing and substance use behaviors persisted when symptom dimensions and parental monitoring were added into the models. Early puberty is a risk factor for substance use particularly among boys. Among girls, the impact of pubertal timing already tempers off during adolescence.

The aim of this study was to study the associations between family structure, parental monitoring and maladjustment outcomes among middle adolescent girls and boys. Data was collected through a school-based survey of a nationally representative sample of 17,643 Finnish adolescents aged 14-16 years. The less the parents knew the adolescents' friends and whereabouts, the more common were all the maladjustment outcomes studied. Non-intact family structure was associated with maladjustment and had associations independent of parental monitoring. We conclude that parental involvement with adolescents is conducive to healthy development, and that adolescents need the protection provided by parental supervision. Knowing the adolescent's whereabouts and friends is a concrete and easily measurable way of assessing parents' involvement in the adolescent's life.

Sexual harassment has been studies as a mechanism reproducing inequality between sexes, as gender based discrimination, and more recently, as a public health problem. The role of family-related factors for subjection to sexual harassment in adolescent has been little studied. Our aim was to study the role of socio-demographic family factors and parental involvement in adolescent's persona life for experiences of sexual harassment among 14-18-year-old population girls and boys. An anonymous cross-sectional classroom survey was carried out in comprehensive and secondary schools in Finland. 90953 boys and 91746 girls aged 14-18 participated. Sexual harassment was elicited with five questions. Family structure, parental education, parental unemployment and parental involvement as perceived by the adolescent were elicited. The data were analyzed using cross-tabulations with chi-square statistics and logistic regressions. All types of sexual harassment experiences elicited were more common among girls than among boys. Parental unemployment, not living with both parents and low parental education were associated with higher likelihood of reporting experiences of sexual harassment, and parental involvement in the adolescent's personal life was associated with less reported sexual harassment. Parental involvement in an adolescent's life may be protective of perceived sexual harassment. Adolescents from socio-economically disadvantaged families are more vulnerable to sexual harassment than their more advantaged peers.