Can ADHD Be Accurately Identified in 3-Year-Olds?

What you need to know

• ADHD symptoms in 3-year-olds can predict continued ADHD symptoms at age 5, but with moderate accuracy
• Combining parent reports, teacher reports, and impairment information improves prediction accuracy, especially for boys
• Many children with early ADHD symptoms may not show continued symptoms later, so caution is needed in early diagnosis

Background on ADHD in young children

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental condition characterized by persistent inattention and/or hyperactivity-impulsivity that interferes with functioning. While ADHD is typically diagnosed in school-age children, symptoms often emerge earlier in the preschool years.

There has been debate about whether ADHD can be reliably identified in very young children. Some experts argue that ADHD-like behaviors in toddlers and preschoolers may simply reflect normal variation in development. Others contend that early identification of ADHD is important to provide timely support.

This study aimed to examine how well ADHD symptoms in 3-year-old children predict continued ADHD symptoms two years later at age 5. The researchers were particularly interested in whether combining information from parents, teachers, and measures of functional impairment could improve prediction accuracy.

How the study was conducted

The study was part of a larger Norwegian research project called the Mother, Father and Child Cohort Study. It included 957 children who were assessed at both age 3 and age 5.

At age 3, parents completed a diagnostic interview about their child’s ADHD symptoms and associated impairments in daily functioning. Teachers also completed questionnaires rating the child’s ADHD symptoms.

At age 5, parents completed a standardized ADHD rating scale. Children scoring above the 95th percentile compared to population norms were classified as having elevated ADHD symptoms.

The researchers then examined how well the various measures at age 3 (parent reports, teacher reports, impairment ratings) predicted which children would show elevated ADHD symptoms at age 5.

Key findings

Some key findings from the study include:

• Parent reports of ADHD symptoms at age 3 were moderately accurate in predicting elevated symptoms at age 5, correctly identifying about 45% of cases (sensitivity) while also correctly ruling out about 85% of children without later symptoms (specificity).

• Adding information about functional impairment slightly improved prediction accuracy.

• Teacher reports added predictive value for boys, but not for girls. Teachers appeared to have more difficulty identifying ADHD symptoms in 3-year-old girls.

• The highest prediction accuracy was achieved by combining parent reports, teacher reports, and impairment information. This identified a small group of children (about 2% of the sample) who had a 64-76% chance of showing elevated ADHD symptoms at age 5.

• However, many children with ADHD symptoms at age 3 did not show elevated symptoms at age 5, and some children developed new symptoms between ages 3-5.

Interpreting the results

These findings suggest that ADHD symptoms can be identified as early as age 3 with some degree of predictive validity. However, there are important limitations to consider:

• Even the most accurate prediction methods still missed many children who later developed ADHD symptoms and incorrectly flagged some children whose early symptoms resolved.

• The study only followed children to age 5, so longer-term outcomes are unknown. Some children may develop ADHD symptoms later in elementary school.

• The study relied on questionnaires and interviews rather than full clinical evaluations, so results may differ from formal ADHD diagnoses.

• Cultural factors may influence results, as this was a Norwegian sample that may not generalize to other countries.

Implications for parents and clinicians

For parents of preschoolers with ADHD-like behaviors, these results suggest:

• Early signs of ADHD at age 3 should be taken seriously, as they do predict increased risk of continued symptoms. However, many children will outgrow early symptoms.

• Getting perspectives from both parents and teachers is valuable, though teachers may be less reliable for identifying ADHD in girls.

• Looking at how much the behaviors interfere with daily functioning is important, not just symptom counts.

• Close monitoring over time is ideal, as ADHD patterns may change between ages 3-5.

For clinicians, the findings indicate:

• Use caution in diagnosing ADHD before age 5, as many children’s symptoms will resolve. Focus on providing support rather than labels.

• Gather information from multiple sources (parents, teachers, direct observation) when evaluating young children for ADHD.

• Pay attention to functional impairment, not just symptom checklists.

• Be aware that teachers may underidentify ADHD symptoms in preschool girls.

• Continued follow-up is important, as some children may develop new ADHD symptoms between ages 3-5.

Conclusions

• ADHD symptoms can be identified in children as young as 3 years old, but with only moderate predictive accuracy for later symptoms.
• Combining reports from parents and teachers along with impairment ratings provides the best prediction, but is still imperfect.
• Many children with early ADHD symptoms will not show continued problems, highlighting the need for caution in early diagnosis.
• Close developmental monitoring over time is ideal for young children with ADHD-like behaviors.