To identify and describe distinct trajectories of cognitive and socioemotional development during childhood and to examine their relationships with adolescent health.

We used group-based multitrajectory modeling applied to longitudinal data on 11 564 children up to age 14 years from the UK Millennium Cohort study to identify trajectories of cognitive and socioemotional development measured using validated instruments. We assessed associations between the derived trajectories and baseline socioeconomic, parental, and school factors using multinomial regression. Logistic regression was used to assess associations between trajectory groups and adolescent health at age 14 and 17 years.

Four child development trajectories were identified: “no problems” (76.5%); “late socio-emotional problems” (10.1%); “early cognitive and socioemotional problems” (8.6%); and “persistent cognitive and socioemotional problems” (4.8%). Those in the problem trajectories were more socioeconomically disadvantaged. Compared with the “no problem” trajectory, the “late socioemotional problems” trajectory had increased odds of overweight and mental ill-health at age 14 years of 1.50 (95% CI 1.24-1.81) and 2.51 (2.03-3.10), respectively. For the “persistent problems” group, the OR for overweight was 1.41 (1.04-1.91), and for mental ill-health, 3.01 (2.10-3.30). For both groups, the associations persisted to age 17 years.

In a representative UK cohort, groups of distinct trajectories of cognitive and socioemotional development were identified. Adverse development, if unresolved, can have a negative impact on weight and mental health in adolescence. Socioemotional development was the main driver of the impact on adolescent health and this requires emphasis in child health policy.