BACKGROUND: Relatively little is known about the relationships between psychiatric symptoms, diagnosis and psychosocial impairment. AIMS: To examine these contemporaneous relationships and prognostic significance in a large general population sample. METHOD: Symptoms of major depression, conduct and oppositional defiant disorders were assessed by interview in two waves of the Virginia Twin Study of Adolescent behavioural Development (2800 children aged 8-16 years). RESULTS: Many children below the DSM-III-R diagnostic threshold, especially for depression, had symptom-related impairment, whereas many children reaching the symptom threshold for conduct and oppositional defiant disorders were little impaired. Impairment score was linearly related to symptom count, with no evidence of any additional impairment at the diagnostic threshold. For depression, only symptoms predicted later symptoms and diagnosis. For conduct and oppositional defiant disorders, impairment was additionally predictive of later symptoms and diagnosis. CONCLUSIONS: Impairment, in addition to symptoms, is important for both nosology and prognosis.
BACKGROUND: Relatively little is known about the relationships between psychiatric symptoms, diagnosis and psychosocial impairment. AIMS: To examine these contemporaneous relationships and prognostic significance in a large general population sample. METHOD: Symptoms of major depression, conduct and oppositional defiant disorders were assessed by interview in two waves of the Virginia Twin Study of Adolescent behavioural Development (2800 children aged 8-16 years). RESULTS: Many children below the DSM-III-R diagnostic threshold, especially for depression, had symptom-related impairment, whereas many children reaching the symptom threshold for conduct and oppositional defiant disorders were little impaired. Impairment score was linearly related to symptom count, with no evidence of any additional impairment at the diagnostic threshold. For depression, only symptoms predicted later symptoms and diagnosis. For conduct and oppositional defiant disorders, impairment was additionally predictive of later symptoms and diagnosis. CONCLUSIONS: Impairment, in addition to symptoms, is important for both nosology and prognosis.