Objective To test the hypothesis that younger children in a school year are at greater risk of emotional and behavioural problems.
Design Cross sectional survey.
Setting Community sample from England, Scotland, and Wales.
Participants 10 438 British 5-15 year olds.
Main outcome measures Total symptom scores on psychopathology questionnaires completed by parents, teachers, and 11-15 year olds; psychiatric diagnoses based on a clinical review of detailed interview data.
Results Younger children in a school year were significantly more likely to have higher symptom scores and psychiatric disorder. The adjusted regression coefficients for relative age were 0.51 (95% confidence interval 0.36 to 0.65, P < 0.0001) according to teacher report and 0.35 (0.23 to 0.47, P = 0.0001) for parental report. The adjusted odds ratio for psychiatric diagnoses for decreasing relative age was 1.14 (1.03 to 1.25, P = 0.009). The effect was evident across different measures, raters, and age bands. Cross national comparisons supported a "relative age" explanation based on the disadvantages of immaturity rather than a "season of birth" explanation based on seasonal variation in biological risk.
Conclusions The younger children in a school year are at slightly greater psychiatric risk than older children. Increased awareness by teachers of the relative age of their pupils and a more flexible approach to children's progression through school might reduce the number of children with impairing psychiatric disorders in the general population.
Many studies have shown that the youngest children in a school year tend to be disadvantaged by the educational system. (1-4) As different countries use different cut-off dates for school entry, national comparisons are illuminating. Whereas children born between September and December are at an advantage in England, where they are the oldest in their class, children born in these months are at a disadvantage in Sweden, where they are the youngest in their class. (5) This is strong evidence for a "relative age" explanation based on the disadvantage of youth rather than a "season of birth" explanation based on seasonal variation in biological risk--for example, for prenatal infection. The educational disadvantage experienced by the youngest children in a class is not confined to the early school years but persists into secondary education and influences university entrance. (2 6)
A study conducted in London more than 20 years ago suggested that "relative age" also influenced the rate of mental health problems in children. (7) We have re-examined this association. As "season of birth" has previously been linked to mental health problems, (8) we used the different cut-off dates for school entry in Scotland and in England and Wales as a "natural experiment" to evaluate the likely cause of psychological disadvantage for the youngest children.
We used data collected in 1999 on a nationally representative sample of British 5-15 year olds. (9) In England and Wales, the cut-off date for school entry is 1 September; children must start school in the academic year during which they will become 5 years old. We followed the educational tradition of dividing...