Time trends in adolescent mental health.
Level 3 - non-randomized controlled study
Repeated cross-sectional comparison across three national population cohorts
PubMed 15482496 · doi:10.1111/j.1469-7610.2004.00842.x
What was done
The authors examined time trends in conduct, hyperactive, and emotional problems over a 25-year period in three UK population-based adolescent samples. Data were derived from parent-completed questionnaires for 15- to 16-year-olds in the National Child Development Study (1974), the 1970 British Cohort Study (1986), and the British Child and Adolescent Mental Health Survey (1999). Longitudinal outcomes in the first two cohorts were evaluated to determine whether reporting thresholds changed over time.
What was found
The abstract reports a substantial increase in adolescent conduct problems between 1974 and 1999 that affected males and females across all social classes and family structures; no specific numerical rates, percentages, or odds ratios are provided in the abstract. There was evidence for a recent increase in emotional problems, whereas evidence on hyperactive behavior trends was mixed. Longitudinal tracking showed similar long-term outcomes for adolescents with conduct problems in earlier cohorts, indicating consistent reporting thresholds over time.
Why it matters
By applying standardized questionnaires across multiple national birth cohorts, this study provides evidence that secular rises in adolescent behavioral and emotional difficulties reflect real population shifts rather than artifacts of altered diagnostic definitions or reporting practices.
Limits
The abstract provides no sample sizes or quantitative effect estimates. Assessments relied solely on parent reports rather than clinical diagnoses or multi-informant reports (such as teachers or adolescents themselves). Findings are restricted to UK adolescents aged 15–16 and may not generalize to other age ranges or geographic regions.