Background: Studies in recent years have shown a significant increase in problematic internet use. Prolonged internet usage negatively impacts various aspects of adolescents’ lifestyles. Methods: The survey was conducted in three Lithuanian cities—Vilnius, Klaipėda, and Molėtai—between October and December of 2023. The survey involved students between the ages of 12 and 16. The participants completed a questionnaire that included questions about wellness and happiness, the Internet Addiction Test (IAT), and the Strengths and Difficulties Questionnaire (SDQ). Our study aimed to investigate problematic internet use among Lithuanian adolescents and its relationships with wellness, happiness, and mental health. Results: This study included 1412 adolescents, with a mean age of 14.41 ± 1.20, with the sample composed of 52.3% boys. Boys indicated that they felt healthier and happier than girls (69.4% vs. 47.4%; 51.4% vs. 29.6%), p < 0.001. A total of 20.8% of students had IAT scores that reflect a normal level of internet usage. For IAT, the average score of girls was statistically significantly higher than that of boys (41.87 ± 12.24 vs. 39.96 ± 12.37), p < 0.001. The IAT score was higher in the group of students who felt less happy and healthy, had more frequent headaches or abdominal pain, and had problems with sleep, p < 0.001. A statistically significant, positive weak correlation was found between students’ IAT scores and SDQ internalizing and SDQ externalizing scores (r = 0.366; r = 0.385, p < 0.001). Conclusions: Prolonged internet use is arising as a serious problem among adolescents. Negative feelings, unhappiness, and poor emotion regulation have an association with internet addiction. Also, the female gender may be more associated with possible internet addiction. The results of this study can serve as initial steps toward developing preventive interventions.

Background: Happiness and health are crucial elements of adolescents’ lives that significantly impact mental well-being and societal engagement. This article hypothesizes that a suitable school environment may be one of the components that can impact students’ subjective feelings of happiness and health. This research aimed to determine the association between a negative school environment, such as experiencing bullying and feeling insecure at school, and students’ happiness and health. Methods: The study was conducted in 2023, surveying students in grades 7–10 from two Lithuanian cities and their districts. The study included 1992 students (females 50.2%) with a mean age of 14.53 ± 1.12. Results: It was observed that male students felt healthier and happier than females. Also, male students felt safer at school more often than females. A positive correlation was found between a student’s feeling of safety at school and their happiness and health. Regression analysis revealed that a feeling of safety at school was the most significant positive factor associated with male students’ sense of happiness and health. Also, the most important factors for females were a feeling of safety at school, bullying, and how often teachers stop bullying. Conclusions: It was found that feelings of insecurity at school, experiences of bullying, and how often teachers stop bullying can be associated with students’ subjective feelings of happiness and well-being. School environmental factors can affect students’ happiness and well-being differently depending on gender. It is essential to focus on vulnerable student populations when creating preventive programs to enhance adolescents’ sense of safety in schools.

Background: Bullying is a significant problem worldwide and in Lithuania, especially among children and adolescents. This study aimed to assess the associations of bullying with adolescents’ subjective sense of happiness and general health. Methods: A cross-sectional study was conducted using an anonymous written questionnaire. Adolescents at various schools across Lithuanian cities and districts were surveyed to investigate the frequency of bullying among them over the past six months and its impact on their subjective sense of happiness and well-being. Results: This study included 4124 students from seventh to tenth grade; their average age was 14.48 ± 1.15 years, with 49.35% being boys. Over the past six months, the highest bullying incidence occurred at school, accounting for 25.79% of the cases. Only half of the respondents (48.81%) felt happy, and a little more than half felt healthy (63.11%). It was found that bullying at school (ρ_s = −0.224; ρ_s = −0.197), outside school (ρ_s = −0.207; ρ_s = −0.180), and online (ρ_s = −0.175; ρ_s = −0.110) is associated with adolescents’ sense of happiness and health. Conclusion: Bullying is common among Lithuanian adolescents and has a negative impact on their subjective happiness and well-being. It is crucial to develop prevention initiatives to decrease bullying in schools and within the community.