Abstract
The patterns of sex differences in psychiatric morbidity are reviewed and hypotheses for the empirical study formulated. Psychiatric treatment and registration for social problems are thoroughly examined in a prospective longitudinal study of a representative birth cohort of 6,482 adolescents. Mental health and psychiatric symptomatology are also checked by a questionnaire. The data obtained are analysed for males and females separately. The results clearly show that there are major sex differences in the pattern of psychopathology in adolescence. These differences are complex and seem related to sex role expectations among parents, adolescents and mental health professionals, and to social factors and the changes experienced in life. The results give some guidelines for the future development of psychiatric care for adolescents.