 The randomized adolescents in each group were not aware of the existence of the other two study groups. This was achievable by programming the attendance of each group at different hours, even on the same days. Moreover their parents were also unaware of the studys design. Finally, all the participants from each of the three groups- both adolescents and parents- were asked not to discuss their study experience until the completion of the follow up, at 6-months from the initiation of the study. 