Clinical experience has repeatedly shown evidence for continuity between mental disorders in children and adolescents and mental disorders in adulthood. Up to now, Austria has had no epidemiologic data on psychiatric diseases in children and adolescents and their development into adulthood. How often do children and adolescents with psychiatric diseases have psychiatric diseases in adulthood? Is there any association between psychiatric diagnoses in childhood/adolescence and adulthood? Electronic medical records provided us with data on 2210 children and adolescents who were admitted to any hospital in the State of Vorarlberg, Austria, between 1997 and 2012 because of psychiatric diseases. In this cross-sectional study, diagnoses were coded according to ICD-10 and ICD-9 criteria. The three main reasons for admission of children and adolescents were substance abuse, emotional disorders and conduct disorders. Of the admitted children and adolescents, 9.8 % were readmitted to a psychiatric institution in adulthood. The main reason for readmission in adulthood appears to be disorders due to psychoactive substances (42.1 %). Of young patients with psychoactive substance use, 9.7 % were rehospitalized in adulthood, 70.8 % of them showed a diagnosis in the same category (F1) on admission. Children and adolescents admitted for schizophrenia, schizotypal, and delusional disorders (F2) were significantly more likely to be readmitted in adulthood (40.9 %) compared to any other child psychiatric diagnosis.This study once again shows the continuity of psychiatric disorders from childhood and adolescence to adulthood. It also gives further information about the transmission of diagnoses when patients reached the age of 18 years and their outcome.Until now, there is hardly any information about the outcome of children and adolescents with psychiatric diagnoses in Austria.We want to bring up more knowledge on that issue. Research findings may improve prevention and clinical assessment of children and adolescents with mental health problems.