How Does Age at School Entry Affect ADHD Symptoms in First Graders?

What you need to know

• Younger children within a grade level show more symptoms of attention-deficit/hyperactivity disorder (ADHD) by the end of first grade compared to their older classmates.
• This “relative age effect” was not apparent at the beginning of the school year, but emerged over the course of first grade.
• The effect was more pronounced in girls than in boys.
• The findings suggest school-related factors may play a role in the development or identification of ADHD symptoms in young children.

Background on ADHD and School Entry Age

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder characterized by persistent inattention, hyperactivity, and impulsivity that interferes with functioning and development. Many studies have found that the youngest children within a grade level are more likely to be diagnosed with ADHD compared to their older classmates. This phenomenon is known as the “relative age effect.”

There are two main hypotheses for why this relative age effect occurs:

1. The oversupply hypothesis suggests that teachers and clinicians may misinterpret normal immature behavior in young children as ADHD symptoms, leading to overdiagnosis.

2. The stress-related hypothesis proposes that the increased academic and social demands of starting school may trigger or amplify ADHD symptoms in younger, less mature children.

To better understand this relative age effect, researchers in Germany conducted a study examining how age at school entry relates to reported ADHD symptoms over the course of first grade.

How the Study Was Conducted

The researchers analyzed data from 1,633 first grade students in the Mainz-Bingen region of Germany. They collected information at four time points:

1. During a preschool health exam
2. 6 weeks before starting first grade
3. 3 months after starting first grade
4. At the end of first grade

Parents completed questionnaires about their child’s behavior at each time point. Teachers also provided behavioral ratings at the end of first grade.

The main measure used was the hyperactivity/inattention subscale of the Strengths and Difficulties Questionnaire (SDQ). This validated screening tool assesses ADHD-related symptoms like restlessness, distractibility, and impulsivity.

The researchers examined how the child’s age when starting school related to their SDQ scores at each time point, while accounting for factors like gender, socioeconomic status, and baseline symptoms.

Key Findings

The study revealed several important findings about the relationship between school entry age and ADHD symptoms:

No Initial Differences

Before starting school and 3 months into first grade, there were no significant differences in parent-reported ADHD symptoms between younger and older children. This suggests the relative age effect was not present at the beginning of the school year.

Emerging Differences by Year End

By the end of first grade, both parents and teachers reported more ADHD symptoms in younger children compared to older classmates:

• For every year increase in school entry age, parent-reported SDQ scores decreased by 0.7 points (on a 0-10 scale).
• Teacher-reported SDQ scores decreased by 1.2 points for each year increase in age.

These associations remained significant even after accounting for baseline symptoms and other factors.

Stronger Effect for Girls

The relative age effect appeared more pronounced for girls than boys. Among girls, a one-year increase in school entry age reduced the odds of having elevated ADHD symptoms (based on SDQ cutoffs) by:

• 89% according to parent reports
• 81% according to teacher reports

For boys, the reductions were 68% and 30% respectively.

No Effect on Clinical Diagnoses

Interestingly, the researchers did not find a significant association between school entry age and rates of actual ADHD diagnoses or medication use during first grade. This may be because there is often a delay between when symptoms first appear and when a clinical diagnosis is made.

Implications of the Findings

These results provide important insights into how the relative age effect on ADHD symptoms develops:

Support for Stress-Related Factors

The fact that age-related differences in ADHD symptoms were not present at the start of school, but emerged over the course of first grade, aligns more closely with the stress-related hypothesis. This suggests that the demands and structure of formal schooling may play a role in triggering or amplifying ADHD-like behaviors in younger children.

Not Just Teacher Misperception

Since both parents and teachers reported more symptoms in younger children by year end, the relative age effect cannot be fully explained by teachers misinterpreting normal immature behavior. The findings indicate real increases in ADHD-related behaviors occur in younger students.

Gender Differences

The stronger relative age effect observed in girls was unexpected. The researchers suggest this could potentially be due to greater academic motivation or pressure among young girls compared to boys. However, more research is needed to understand these gender differences.

Early Identification Important

While clinical diagnoses did not differ by age in first grade, the increases in reported symptoms suggest younger children may be at higher risk for eventually developing ADHD. Early identification of at-risk children could allow for proactive support and intervention.

Practical Implications

These findings have several important implications for parents, educators, and healthcare providers:

For Parents

• Be aware that younger children within a grade may struggle more with attention and behavior, especially as the school year progresses. This doesn’t necessarily mean they have ADHD, but they may need extra support.
• Consider a child’s age relative to classmates when evaluating school readiness or performance concerns.
• Don’t hesitate to discuss any behavioral changes or challenges with teachers and pediatricians.

For Educators

• Recognize that younger students may have more difficulty with attention and impulse control due to relative immaturity, not necessarily ADHD.
• Adjust expectations and provide additional structure/support for younger children within the class as needed.
• Be cautious about recommending ADHD evaluations for young children based solely on classroom behavior early in the school year.

For Healthcare Providers

• Consider a child’s age relative to classmates when evaluating possible ADHD, especially in first grade.
• Look for increases in symptoms over the course of the school year, rather than only assessing at one time point.
• Be aware that the relative age effect may be stronger in girls, even though ADHD is generally more common in boys.

Conclusions

• Younger children within a grade level show increased ADHD symptoms by the end of first grade compared to older classmates.
• This relative age effect emerges over the course of the school year, suggesting school-related factors play a role.
• The effect appears more pronounced in girls than boys.
• While not necessarily indicating ADHD, these age-related increases in symptoms highlight the need for developmentally-appropriate expectations and support for young students.

Overall, this study provides valuable insights into how age at school entry relates to ADHD-like behaviors in early elementary students. The findings emphasize the importance of considering a child’s relative age when evaluating attention and behavior concerns. More research is still needed to fully understand the mechanisms behind this relative age effect and determine the best ways to support young students as they adjust to the demands of formal schooling.