Background: Adolescents face unique challenges as they transition from childhood to adulthood, which can be marked by risky behaviours such as substance use and sexual activities. The present study analyses the relationship between risky sexual behaviour and the use of psychoactive substances, namely alcohol, cannabis, and other illegal substances, among students aged 15–16 years in 23 European countries, to investigate potential between-country differences. Method: Data were extracted from the 2019 European School Survey Project on Alcohol and Other Drugs (ESPAD) cross-sectional survey. Risky sexual behaviour was defined as self-reported unprotected sex. Substance use, other individual risk behaviours, and parenting indicators were investigated as key predictors. Results: A 9.8% of 16-year-old students in Europe reported sexual intercourse without a condom in the past year, and 7.8% had unprotected sex while not using alcohol/drugs, with a higher prevalence observed among males (8.5%) than among females (7.1%). Prevalence ranged from 3.2% in Georgia to 16.0% in Sweden. The multivariate analysis revealed significantly higher odds of engaging in sexual intercourse without a condom in illicit drug users (cannabis, inhalants, cocaine, ecstasy) and heavy episodic drinkers, students who went out in the evening, and those belonging to non-traditional families. Conclusions: Unprotected sex in the past year and substance use are strongly associated amid 16-year-old students in Europe. The prevalence of risky sexual behaviours across European countries does not follow a clear geographical pattern, suggesting that simple macro-level factors, such as broad regional or cultural groupings, may only partially explain prevalence differences.

Adolescents are heavy users of digital media but often lack critical skills, increasing their vulnerability to harmful online content. The integration of game elements into learning and training offers a promising strategy to support positive behavioural change and strengthen adolescents’ skills. This paper describes the development of a conceptual framework for Dress-DIGITARIAN, a serious game aimed at improving health literacy, coping skills, and self-esteem, grounded in Self-Determination Theory (SDT). The framework was constructed to generate higher-order understanding through a multi-level process: analyzing general theory (SDT), integrating mid-range models (the Octalysis framework), and incorporating empirical insights derived from two data collection phases with the target population. This integrative approach informed and guided the game’s design through participatory methods. Developed through collaboration between schools and research institutions, this approach bridges theory and practice by aligning game mechanics with adolescents’ psychological needs. It also underscores the value of involving adolescents in research, not only to enhance scientific rigour but also to empower them as agents of change capable of contributing to health promotion policies and educational innovation. This study does not report the results of a completed intervention or outcome evaluation, which will be conducted in the sixth phase at the end of the current school year. Future research is needed to assess the model’s effectiveness and scalability and to identify areas for further refinement.

Background: Adolescent substance use has evolved substantially alongside broader societal, cultural, and drug–market transformations. However, how patterns of use and associated factors differ across generations remains poorly understood. We examined temporal and generational patterns in illicit substance use among European adolescents over three decades and assessed whether associated factors have evolved across generational cohorts.Methods: We conducted a repeated cross–sectional study using data from the European School Survey Project on Alcohol and Other Drugs, including 767,309 students aged 16 years from 45 participating countries across eight survey waves (1995–2024). Lifetime use of illicit substances was assessed using standardised self–administered questionnaires. Generational cohorts were defined based on survey year (GenX: 1995; GenY: 1999–2011; GenZ: 2015–2024). Temporal trends were examined using weighted prevalence estimates, and differences across generations were assessed using mixed–effects logistic regression models adjusted for sex at birth, with country as a random intercept. Multivariable logistic regression models examined associations between substance use and selected potential associated factors, stratified by generation.Findings: While the prevalence of illicit substance use excluding cannabis remained stable in GenX and GenY (11·7%) and declined in GenZ (10·1%), substance–specific patterns diverged sharply. Cannabis use increased from GenX (14·4%) to GenY (17·0%) and declined in GenZ (13·9%). Ecstasy/MDMA and amphetamine use peaked in GenY and declined in GenZ. Conversely, compared with GenX, GenZ had significantly higher odds of cocaine (OR 3·11 [95% CI 2·84–3·41]) and injection drug (OR 1·96 [95% CI 1·76–2·18]) use. The odds of cannabis use were higher in both GenY and GenZ. Although the associated factors like early initiation, perceived availability, and peer use remained consistent, their association strength intensified in GenZ. Notably, the strength of association for early alcohol intoxication declined, while familial and psychological vulnerabilities showed stronger associations with substance use in the most recent cohort. Interpretation: Adolescent substance use in Europe appears to be undergoing risk reconfiguration rather than uniform decline, with lower overall experimentation but greater concentration of risk in specific substances and subgroups. Although core associated factors remain consistent across generations, their association have strengthened in recent cohorts, highlighting the need for prevention strategies that address evolving generational profiles, early initiation, social environments, and access to substances.