Epidemiological studies as well as evaluation of subjective complaints and psychological characteristics covering big time periods (decades) testify on growing prevalence of a number of subclinical mental health disturbances in adolescents, which often turn into diagnosed disorders. Most frequent disorders in adolescents and young people are anxiety and depression, addictions, as well as behavioral disorders, which are associated with the psycho-social characteristics of this age group. These data most likely reflect the real growth of prevalence and cannot be explained only by changed diagnostic criteria or increased medical awareness. Most probably they are induced by psychosocial stress, associated with social inequalities, information overload, and other global changes that lead to loneliness and low level of social support. For adolescents such factors as changes in individual vulnerability, family factors, wider environment (school, reference groups) and even wider social, economic and other factors provoking psycho-social stress may be essential. Psycho-social stress may program mental health disturbances by triggering epigenetic mechanisms that may be a subject of transgenerational propagation. For better understanding of observed tendencies synthesis of biological, psychological and social approaches is needed.