Objective: The aim of this study was to define the long-term psychiatric outcomes of adolescent internalizing disorder in the general population, using data collected over 40 years from a national birth cohort.
Method: A total of 3,279 members of the Medical Research Council National Survey of Health and Development (the 1946 British birth cohort) underwent assessments of psychiatric symptoms, primarily anxiety and depression, at ages 13 and 15. Adolescents who had internalizing disorder at both ages 13 and 15 and those who had internalizing disorder at one of the two ages were compared with mentally healthy adolescents on various psychiatric outcomes in adulthood (ages 26-53), including the prevalence of mental disorders, self-reported trouble with "nerves," suicidal ideation, and treatment for psychiatric disorders.
Results: About 70% of adolescents who had internalizing disorder at both ages 13 and 15 had mental disorder at age 36, 43, or 53, compared with about 25% of the mentally healthy adolescents. They were also more likely than healthy adolescents to have self-reported "nervous trouble" and to have been treated for psychiatric disorder during adulthood. None of these effects was apparent among subjects who had internalizing disorder at only one of the two adolescent assessments.
Conclusions: The long-term psychiatric outcome for adolescents with persistent or recurrent internalizing disorder was poor, whereas the outcome for those who had a single episode was better than expected. The association between adolescent internalizing disorder and poor psychiatric outcomes in adulthood may be mediated by persistence or severity of symptoms in adolescence.