Lifestyle choices exert a major influence over the present and future health of adolescents. The international study "Health Behaviour in School-aged Children (HBSC)" was created to monitor the social determinants, the health and risk behaviours, and the protective and adverse factors that each influence young adolescents' health. The survey is conducted every four years, and the WHO produced its latest edition in the spring of 2012 (using the 2010 data). We have selected and summarised what seem to be the most important insights for Swiss clinicians. The overall results are satisfactory but some weaknesses remind us that prevention is an ongoing challenge both in private practices and in public policy.