Importance: More than 50% of lifetime mental health disorders develop by early adolescence, and yet it is not well understood how early childhood social-emotional functioning varies in populations or how differences in functioning may be associated with emerging mental health conditions.
Objectives: To identify profiles of social-emotional functioning at kindergarten school entry (age 5 years) and to examine to what extent profiles are related to early-onset mental health conditions (ages 6-14 years).
Design, setting, and participants: This prospective cohort study followed up a population cohort of 34 552 children in British Columbia, Canada, from birth (born 1996-1998) to age 14 years (last follow-up, December 31, 2011). Data were analyzed from the Developmental Trajectories cohort that links British Columbia child development data from the Early Development Instrument (EDI) to British Columbia Ministry of Health and Ministry of Education records. Data were analyzed between May and September 2017.
Exposures: Early childhood social-emotional functioning (defined as social competence, internalizing, and externalizing symptoms) rated by the children's kindergarten teachers.
Main outcomes and measures: Occurrences of physician-assessed mental health conditions throughout childhood and early adolescence, including depression, anxiety, conduct disorder, and attention-deficit/hyperactivity disorder (ADHD), calculated from billing codes from the International Classification of Diseases, Ninth Revision recorded in provincial health insurance data.
Results: Data from 34 323 children (mean [SD] age, 5.7 [0.3] years; 17 538 [51.1%] were boys) were analyzed at kindergarten and followed up to age 14 years (15 204 completed follow-up). Latent profile analysis identified 6 unique social-emotional functioning profiles at school entry, with 41.6% of children (n = 14 262) exhibiting comparative vulnerabilities in internalizing or externalizing behaviors. Prevalence of mental health conditions from ages 6 to 14 years was 4.0% for depression, 7.0% for anxiety, 5.5% for conduct disorder, 7.1% for ADHD, and 5.4% for multiple conditions. Zero-inflated Poisson analyses showed an association between social-emotional functioning profiles at kindergarten school entry and physician-assessed mental health conditions by age 14 years (range of adjusted odds ratios: depression, 1.10 [95% CI, 0.76-1.60] to 2.93 [95% CI, 1.93-4.44]; anxiety, 1.00 [95% CI, 0.74-1.36] to 1.73 [95% CI, 1.11-2.70]; conduct disorder, 2.17 [95% CI, 1.41-3.34] to 6.91 [95% CI, 4.90-9.74]; ADHD, 1.46 [95% CI, 1.11-1.93] to 8.72 [95% CI, 6.46-11.78]; and multiple conditions, 1.20 [95% CI, 0.88-1.63] to 6.81 [95% CI, 4.91-9.44]). Children with higher teacher ratings of aggression and hyperactivity had more frequent consultations for conduct disorder, ADHD, and multiple conditions.
Conclusions and relevance: This study's findings suggest that more than 40% of children enter the school system with relative vulnerabilities in social-emotional functioning that are associated with early-onset mental health conditions. The results raise important questions for using population-level early childhood development monitoring in the context of universal and proactive mental health strategies.