A Review of Canadian Diagnosed ADHD Prevalence and Incidence Estimates Published in the Past Decade

Stacey D Espinet; Gemma Graziosi; Maggie E Toplak; Jacqueline Hesson; Priyanka Minhas

doi:10.3390/brainsci12081051

A Review of Canadian Diagnosed ADHD Prevalence and Incidence Estimates Published in the Past Decade

Brain Sci. 2022 Aug 8;12(8):1051. doi: 10.3390/brainsci12081051.

Authors

Stacey D Espinet¹, Gemma Graziosi², Maggie E Toplak², Jacqueline Hesson³, Priyanka Minhas⁴

Affiliations

¹ CADDRA-Canadian ADHD Resource Alliance, Toronto, ON M5A 3X9, Canada.
² Department of Psychology, York University, Toronto, ON M3J 1P3, Canada.
³ Faculty of Education, Memorial University of Newfoundland, St. John's, NL A1C 5S7, Canada.
⁴ Department of Psychology, University of Calgary, Calgary, AB T2N 1N4, Canada.

Abstract

(1) Background: ADHD is recognized as one of the most common neurodevelopmental disorders. The worldwide prevalence of ADHD is estimated at 5.3%; however, estimates vary as a function of a number of factors, including diagnostic methods, age, sex and geographical location. A review of studies is needed to clarify the epidemiology of ADHD in Canada. (2) Methods: A search strategy was created in PubMed and adapted for MEDLINE and PsycINFO. Papers were included if they examined diagnosed ADHD prevalence and/or incidence rates in any region of Canada, age group and gender. A snowball technique was used to identify additional papers from reference lists, and experts in the field were consulted. (3) Results: Ten papers included in this review reported on prevalence, and one reported on incidence. One study provided an overall prevalence estimate across provinces for adults of 2.9%, and one study provided an overall estimate across five provinces for children and youth of 8.6%. Across age groups (1 to 24 years), incidence estimates ranged from 0.4% to 1.2%, depending on province. Estimates varied by age, gender, province, region and time. (4) Conclusions: The overall Canadian ADHD prevalence estimate is similar to worldwide estimates for adults. Most studies reported on prevalence rather than incidence. Differences in estimates across provinces may reflect the varying number of practitioners available to diagnose and prescribe medication for ADHD across provinces. To achieve a more comprehensive understanding of the epidemiology of ADHD in Canada, a study is needed that includes all provinces and territories, and that considers estimates in relation to age, gender, ethnicity, geographical region, socioeconomic status and access to mental healthcare coverage. Incidence rates need further examination to be determined.

Keywords: ADHD; Canada; epidemiology; incidence; prevalence.

Publication types

Review

Grants and funding

This research received no external funding. CADDRA—Canadian ADHD Resource Alliance provided in-kind funding in support of the manuscript administration.