Introduction
Despite all advances in technology and medicine, the protection of the health of youth is at risk under present-day conditions. The widespread idea that children and adolescents have a particular vitality and good health seems to be challenged by the confirmed health impairments and health-threatening behaviors. Although it has been possible to successfully suppress the traditional, mostly infectious diseases, new kinds of health risks and diseases are being exhibited in this age group as well as health-threatening behaviors and lifestyles, which can be traced back, in part, to long-term strains on physical, mental, and social adaptation (Hurrelmann and Lösel, 1990; Lösel and Bender, 1991; Millstein, 1989).
The high incidence of psychosomatic complaints, chronic disease, and mental disorder, as well as behavioral health risks to which adolescents are exposed through drug use, careless behavior in driving automobiles, poor nutrition, insufficient physical exercise, unprotected sexual activity, and self-destructive and aggressive behavior, has shown a marked increase in recent years (Engel and Hurrelmann, 1989; Remschmidt, 1987; Weber, 1990). The causes of these many-sided phenomena of psychosocial risk and strain are found at least partially in living conditions, and in the conditions of the natural, social, and technological environments (Hurrelmann, 1989). Only too clearly, the results of research on the health of the young have shown that major factors of health impairment and health-threatening behaviors in children and adolescents are due to changed living conditions. Less stable family relationships, increasing achievement demands, consumer and leisure-time stress, and pluralized values provide external conditions that impede the development of a stable personality and an accompanying healthy lifestyle during adolescence (Engel and Hurrelmann, 1993; Nordlohne, 1992).