Trial results for a study investigating strategies to reduce the impact of the relative age effect in kindergarten for children with Attention Deficit Hyperactivity Disorder (ADHD) were posted on ClinicalTrials.gov on 2025-11-19, with 62 participants enrolled.
Background
Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder often diagnosed in childhood. Research indicates that children who are relatively young for their kindergarten grade, meaning those born in the months immediately preceding the school entry cut-off, face a significantly higher risk of receiving an ADHD diagnosis and being prescribed stimulant medication. This phenomenon, known as the "Relative Age Effect," is primarily linked to age of entry when other factors are controlled, and can have substantial implications for young children, including an increased likelihood of being prescribed psychoactive medication to manage behavior.
Trial design
This completed study, designated as Phase NA, enrolled 62 participants to investigate conditions including Attention Deficit Hyperactivity Disorder. The trial explored strategies to reduce the impact of the relative age effect in kindergarten. The study compared a "School as Usual" group with an "Immediate Relative Age Effect Intervention" group and a "Delayed Relative Age Effect Intervention" group.
Key results
The trial reported several key measurements using the Disruptive Behavior Disorders Rating Scale across the different groups:
- For one measurement instance:
- The "School as Usual" group had a mean score of 0.8 (Standard Deviation 0.51) units on the scale.
- The "Immediate Relative Age Effect Intervention" group had a mean score of 1.12 (Standard Deviation 0.8) units on the scale.
- The "Delayed Relative Age Effect Intervention" group had a mean score of 1.03 (Standard Deviation 0.72) units on the scale.
- For a second measurement instance:
- The "School as Usual" group had a mean score of 1.33 (Standard Deviation 0.83) units on the scale.
- The "Immediate Relative Age Effect Intervention" group had a mean score of 1.15 (Standard Deviation 0.70) units on the scale.
- The "Delayed Relative Age Effect Intervention" group had a mean score of 1.28 (Standard Deviation 0.85) units on the scale.
- For a third measurement instance:
- The "School as Usual" group had a mean score of 1.34 (Standard Deviation 0.91) units on the scale.
- The "Immediate Relative Age Effect Intervention" group had a mean score of 1.13 (Standard Deviation 0.80) units on the scale.
- The "Delayed Relative Age Effect Intervention" group had a mean score of 1.00 (Standard Deviation 0.65) units on the scale.
- For a fourth measurement instance:
- The "School as Usual" group had a mean score of 1.19 (Standard Deviation 0.58) units on the scale.
- The "Immediate Relative Age Effect Intervention" group had a mean score of 1.12 (Standard Deviation 0.83) units on the scale.
- The "Delayed Relative Age Effect Intervention" group had a mean score of 1.05 (Standard Deviation 1.03) units on the scale.
What this means
The posted results provide preliminary data on disruptive behavior scores in kindergarten children under different relative age effect interventions compared to usual school practices. The mean scores and standard deviations for the Disruptive Behavior Disorders Rating Scale show variability across the intervention groups and the control. Without further statistical analysis or specified primary endpoints, definitive conclusions about the comparative efficacy of the interventions cannot be drawn from these raw measurements. However, these data contribute to understanding the impact of age-related entry effects on behavior in young children and the potential role of specific interventions.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for the study NCT05142826, titled "Investigation of Strategies to Reduce the Impact of the Relative Age Effect in Kindergarten", were posted on 2025-11-19 on clinicaltrials.gov.