Objective: This prospective longitudinal study of a representative community sample of children and adolescents (N = 269) examined the long-term course and predictive power of psychiatric symptoms in childhood/adolescence for diagnostic outcome (ICD-10) 18 years later at adult age.
Method: At both cross-sectional assessments, baseline (1980-1984) and the 18-year follow-up (2001-2004), psychiatric symptoms were assessed using the 'Standardized Psychiatric Interview' (Goldberg et al. in Br J Prev Soc Med 24:18-23, 1970). At follow-up, study participants were reassessed with the standardized M-CIDI (Wittchen and Pfister in Manual und Durchführungsbeschreibung des DIA-X-M-CIDI, Swets and Zeitlinger, Frankfurt, 1997) interview.
Results: The participation rate at 18-year follow-up was 82% of those alive. The frequency of clinically relevant depressive symptoms and symptoms of anxiety or phobia was considerably higher when the participants were younger (baseline assessment at childhood, adolescent age) as compared to their scores in adult age. Increased levels of somatic symptoms, fatigue, irritability, sleep disturbances, depression, anxiety and worry as well as phobic symptoms in childhood/adolescence were related to a higher risk of suffering from a psychiatric disorder in adulthood. Depressive symptoms predicted both mood disorders and substance use disorders in adulthood. Phobias predicted later anxiety disorders.
Conclusion: These data spanning almost two decades add significant information to the existing literature on the course of mental disorders in the community during the transition from adolescence to adulthood.