Identify the type of research design (method) used in the study (i.e. observation, correlation, experiment). The sample was composed of 1,652 fifth to 11th grade students aged 11.1 to 17 at the beginning of the study from six schools randomly selected from an initial pool of 38 schools in three representative geographical areas in Israel. The schools were representative of schools nationwide in terms of regional distribution, school type, and socioeconomic status (SES), according to data available from the Israeli Ministry of Education. The initial pool of schools was recruited with the assistance of the local municipal Education Departments that agreed to take part in a national study on children's and adolescents' mental health and well-being