Fifty years of epidemiologic studies in child and adolescent psychiatry in Sweden

In Sweden the first epidemiologic study on mental disorders in children and adolescents was made in 1945-46. Since then investigations have been made on different age groups using various methods to clarify the nature and magnitude of psychiatric morbidity in children and adolescents. During the last two decades the assessment of single behaviour deviances and stress reactions has been replaced by studies on psychiatric disorders according to the DSM system or using factor-analysed composite clusters of behaviours. High rates of comorbidity show that the symptoms of young people are more diffuse than those of adults. The frequency of ''psychiatric cases'' varied depending on the methods used. Most studies rate 5-20% as behaviourally disturbed i.e. enough to cause a problem to the child and/or his/her parents and teachers. Most studies state that boys have more behaviour deviances than girls before puberty. Girls have more problems during adolescence, especially depressions and psychosomatic symptoms. Girls have more internalizing symptoms, while boys display more acting-out behaviours. Self-reported symptoms are generally more frequent than symptoms reported by parents. Teachers report the lowest frequencies. Severe psychopathology like anorexia nervosa, major depressive disorders and psychoses are comparatively rare. The study of such conditions requires different methods than the study of adjustment problems and stress reactions.