Module 3: Assessment

Lesson 4

Epidemiology of ADHD

The worldwide prevalence of ADHD is 5.3% (Polanczyk et al., 2007).
In Canada, ADHD affects about 5% of the school-age population (Statistics Canada, 2015).

In the 2006/07 Canadian National Population Health Survey on children aged 3 to 9 years found the following:

  • Percent of children using ADHD medication who have a diagnosis of ADHD in 2007:
    • 76.3% of all children in the sample
    • 43.7% of preschoolers
    • 78.0% of school-age
    • 75.7% of boys
    • 78.4% of girls
  • Many individuals diagnosed with ADHD have co-occurring conditions:
    • 50-90% of children with ADHD have at least one comorbid condition;
      • Approximately half of all children diagnosed with ADHD have at least two comorbidities;
    • 85% per cent of adults diagnosed with ADHD meet criteria for a comorbid condition.