BACKGROUND

Attention deficit/hyperactivity disorder (ADHD), a well described, common problem affecting school-aged children, has an estimated prevalence in Ontario of 7% to 10% of boys and 3% of girls in the age range of four to 11 years. There has been a documented trend to increased use of stimulant medications in the treatment of this disorder in the United States.

OBJECTIVE

To assess the prevalence of stimulant medication therapy for ADHD in three southern Ontario school boards.

PATIENTS AND METHODS

A cross-sectional epidemiological study was performed by distributing a survey to all parents of children in kindergarten through grade 6 in six to eight schools selected randomly in each of the three participating school boards. The completed questionnaires were collated, and the comparative data were analyzed using chi(2).

RESULTS

A total of 5100 surveys were distributed among the three school boards; 1465 (28.8%) questionnaires were returned completed. Within the three school boards - Hastings County Board of Education, Metropolitan Toronto Separate School Board and the East York Board of Education - the prevalence of ADHD for the age groups surveyed was 4.3%, 3.4% and 6.8%, respectively (average 4.7%), with a peak average of almost 9% by 12 years of age. The percentages of children with diagnosed ADHD who were on stimulant medication were 43%, 3% and 13%, respectively. The differences between the school boards were statistically significant (P<0.05). The male versus female prevalence of a diagnosis of ADHD was 7.1% versus 1.2%, 3.8% versus 3.3% and 10.1% versus 3.6%, respectively, with a combined school board average of 7.1% of males versus 2.9% of females. The average percentage of males versus females who were diagnosed with ADHD and who were on stimulant medication was found to be 27% versus 5%.

CONCLUSIONS

The prevalence of ADHD was 4.7% in the study population. The overall percentage of children who were on stimulant medication was approximately 1%. Males were not only more likely to be diagnosed with ADHD but also more likely to be treated with stimulant medications if diagnosed. There was an increased prevalence of ADHD with older age, and the different school boards had significant differences in both the percentages of children who were diagnosed with ADHD and the percentages of children who were on medication, suggesting that individual school board policies or other factors may affect both the rate of diagnosis and the likelihood of stimulant drug treatment.