Participants in this arm will receive the game intervention including 15-30 minutes of digital health game playing at school and 2 weeks of free usage of the game during free time and a 30-minute debriefing session with a researcher.

The participants in this arm will receive no intervention.

Game intervention consists of 15-30 minutes digital health game playing at school and 2 weeks free usage of the digital health game during free time. In addition, after the 2 weeks period of game playing, 30-minute debriefing sessions with a research are held.

The digital health game includes visualized elements with sound effects that aim at increasing understanding about the consequences of tobacco product use and supporting refusal skills. The health game includes different mini-games and also textual information.

The debriefing sessions with a researcher include small group and group discussions about the themes presented in the game. A researcher leads and teachers facilitate the discussions. The debriefing sessions aim to connect the game experience with daily life situations.

Assessed with a smoking refusal self-efficacy scale (scores 6-24; higher scores indicate stronger smoking refusal self-efficacy).

Subscales for cigarette use (7 items) and snus use (7 items). Both are assessed with a 4-point Likert-scale questionnaire.