Table 1.

Summary of ten research articles related to the prevalence and incidence estimates of ADHD in Canada.

Name of Study	Age Range	Geographic Location	Sample	Statistic	Prevalence Estimate	Incidence Estimate	Case Definition	Data Source	Gender	Ethnicity
Braut & Lacourse (2012) [11]	Children: 3 to 9 years	All provinces	Three cross-sectio nal samples of nonreferred children, 1994–1995: n = 12,595, 2000–2001: n = 13, 904, and 2006–2007: n = 14,655. (Number of individuals with ADHD not reported.)	Number of children with ADHD over total number of children, both overall and for each subgroup.	Overall prevalence from 2000 to 2007: 1.7% to 2.6%. Preschoolers: 0.5% to 1.1%, School-age children: 2.2% to 4.1%.	—	The presence of a child’s psychiatric diagnosis of ADHD was reported by the parent most knowledgeable about the child.	National Longitudin al Survey on Children and Youth. Household s were selected through the Statistics Canada’s Labour Force Survey	Male: 51.0% Female: 49%	—
Morkem, Han delman, Queenan, Birtwhistl, & Barber. (2020) [12]	Children and youth: 4 to 17 years, Young adults: 18 to 34 years, Adults: 35 to 64 years	Alberta, Manitoba, Ontario, Quebec, Newfoundland	Any patient, 2008 to 2015, who received care from their primary care clinic in the year of study or the preceding year, N = 19,683, n = 246 with ADHD.	The case definition of ADHD was applied to each yearly practice population n to produce a count of those with ADHD; number of patients with ADHD over total number of patients for each given year.	Prevalence from 2008 to 2015 4- to 17- year olds: 6.9% to 8.6%, 18- to 34-year olds: 5.7% to 7.3%, 35- to 64-year-olds: 5.2% to 5.5%.	—	Patient was 4 years of age or older and either (a) the medical record included ICD-9 code 314 in one or more visits, and one or more prescriptions of ADHD-related medications; or (b) the medical record included ICD-9 code 314 in two or more visits. The EMR algorithm was validated by conducting a manual electronic chart review of a sample of 492 patients by a blinded abstractor.	Canadian Primary Care Sentinel Surveillance Network (CPCSSN) (a repository of primary care EMR data)	Male: ~42.9% Female: ~57.1% (Gender distribution was not reported in the paper)	—
Connolly, Speed, & Hesson. (2016) [13]	Adults: 20 to 64 years	All provinces	Population-based sample, 2012, N = 17,311, n = 377 with ADHD	Total number of respondents who said that they have been diagnosed with ADD/ADH D over total number of respondents.	Overall prevalence: 2.7%.	–	As part of the CCHS-MH interview, respondents were asked, “Do you have attention deficit disorder?”	Public Use Microdata File of the 2012 Canadian Community Health Survey (CCHS; Statistics Canada, 2013)	Male: 52.1% Female: 47.9%	White: 80.6% Non-White: 19.4%
Hesson & Fowler (2018) [14]	Adults: 20 to 64 years	All provinces	Population-based sample, 2012, N = 16,957, n = 488 with ADHD	Total number of respondents who said that they have been diagnosed with ADD/ADHD over total number of respondents.	Overall prevalence: 2.9%.	–	As part of the CCHS-MH interview, respondents were asked, “Do you have attention deficit disorder?”	Public Use Microdata File of the Canadian Community Health Survey–Mental Health (CCHS-MH ) 2012 (Statistics Canada, 2013)	Male: 58.8% Female: 41.2%	—
Vasiliadis, Diallo, Rochette, Smith, Langille, Lin, et al. (2017) [15]	Children and Youth: 1 to 17 years, Young adults: 18 to 24 years	Manitoba, Ontario, Quebec, Nova Scotia	Young adults who received a Primary diagnosis of a mental disorder between 1999 and 2012. (N, total sample size, and n, number of individuals with ADHD, not reported.)	Incidence and prevalence were calculated yearly. Annual prevalence: proportion of persons who had received a primary diagnosis of ADHD in a given year. Annual incidence: proportion of new cases in the year who had not previously received an ADHD diagnosis.	Annual age-standardized prevalence from 1999 to 2012 1- to 17-year-olds: Nova Scotia: 2.2% to 3.8%, Manitoba: 1.5% to 2.8%, Quebec: 1.1% to 3.8%, Ontario: 1.1% and 1.1%. 18-to 24-year-olds Nova Scotia: 0.5% to 1.7%, Manitoba: 0.2% to 0.8%, Quebec: 0.1% to 0.7%, Ontario: 0.2% and 0.5%.	Incidence from 1999 to 2012 1- to 24-year-olds: Nova Scotia: 0.8% to 1.0%, Manitoba: 0.6% to 0.8%, Quebec: 0.5% to 1.2%, Ontario: 0.5% to 0.4%.	At least 1 physician visit or hospitalization within a given year with the following primary diagnoses: 314 for ICD-9 or the equivalent ICD-10 code (F90.x). Diagnoses could be performed by general practitioners, paediatricians, psychiatrists, or other specialists.	Administra tive linked patient data from Manitoba, Ontario, Quebec, and Nova Scotia. Obtained from the same sources as the Canadian Chronic Diseases Surveillance Systems (Med-Ech o in Quebec, the Canadian Institute of Health Information Discharge Abstract Database in the 3 other provinces, plus the Ontario Mental Health Reporting System).	—	—
Yallop, Brownell, Chateau, Walker, Warren, Bailis et al. (2015) [16]	Adults: 18 to 29 years	Manitoba	Cross sectional analysis of adults, 2007/08 to 2008/09, N = 207,544, n = 14,762 with ADHD.	Number of people with ADHD diagnosis over total study population.	Overall lifetime prevalence: 7.1%.	–	Lifetime prevalence of Diagnosis determined from physician visits and hospitalizations, using the ICD-9-CM of 314 (hyperkinetic syndrome of childhood) or the ICD-10-CA code of F90 (hyperkinetic disorders). In addition, people who had 2 or more prescriptions for a psychostimulant and no diagnosis for conduct disorder, narcolepsy, or catalepsy.	The Manitoba Population Health Research Data Repository	Male: 50.5% Female: 49.5%	–
Leung, Kellett, Youngson, Hathaway & Santana (2019) [17]	Children and youth: 18 years of age or under	Alberta	Population-based sample, 2015, N = 144,243. (n, number of individuals with ADHD, not reported.)	Prevalence was calculated yearly. Annual prevalence: number of cases in cohort each year over annual provincial population, multiplied by 1000 to obtain rates per 1000 people.	Prevalence from 2008 to 2015 Females: 3.1% to 3.9% Males: 8.0% to 9.5%.	–	Child (age ≤ 18 years) with at least one physician visit or hospitalization with a primary diagnostic code corresponding to one of the psychiatric disorders of interest (ICD-9 or ICD-10).	Retrospective analysis of six administrati ve databases, 2008–2015, Alberta: Discharge Abstract Database (DAD), Practitioner Claims Database, National Ambulatory Care Reporting System (NACRS, since 2010), Alberta Ambulatory Care Reporting System (AACRS, before 2010), Provincial Registry, and Pharmaceutical Information Network (PIN).	Male: ~ 59.3% Female: ~ 40.7%	—
Hauck, Lau, Wing, Kurdyak & Tu (2017) [18]	Children and youth: 1 to 24 years	Ontario	Population-based sample, 2002–2012, N = 10,000, n = 536 Individuals with ADHD.	Number of definite cases of ADHD in the cohort over total number of included cases.	Overall prevalence: 5.4% Males: 7.9% Females: 2.7%.	—	Charts in which the family physician recorded a diagnosis of ADHD (reason for visit ICD10 diagnosis was F00 to F99 OR X60-X84), if a neuropsychological test or report indicated a diagnosis, or if correspondence from a school/school board indicated a diagnosis of ADHD.	Medical records contained in the Medical Record Administrati ve data Linked Database (EMRALD).	Male: 50.6% Female: 49.4%	—
Sareen J, Bolton SL, Mota N, et al.: (2018) [19]	60% over 50 years old (no other data reported on age of sample)	No data on geographic location of sample provided	N = 2941 Canadian Forces members and veterans, 2018	Total number of participants who have been previously diagnosed with ADHD over the total number of participants.	Overall prevalence 2018: 3.3%	—	Self-report health professional diagnosis of ADHD based on DSM-IV	Two-wave 2002–2018 Canadian Armed Forces Members and Veterans Mental Health Follow-up Survey (CAFVMHS)	Male: 87.8%; Female: 12.2%	—
Gadderm an, Petteni, Janus, Puyat, Guhn & Georgiades (2022) [20]	Children and youth: Birth to 19 years	British Columbia	Population- based sample, 1996–2016, N = 470,464 Non-immigrant, comparison sample: n = 307,902 (n, non-immigrant sample with ADHD, not reported, n = ~ 53,914) Refugee: n = 19,686 Immigrant: n = 142,011	Total number of participants who have been previously diagnosed with ADHD over the total number of participants. Overall estimates adjusted for years living in British Colombia.	Overall prevalence from 1996 to 2016: Non-immigrant, comparison sample: 3–5 years: 1.3% 6–12 years: 9.2% 13–19 years: 7.0% First-generation immigrant: 3–5 years: 0.8% 6–12 years: 4.3% 13–19 years: 2.1% Second-generation immigrant: 3–5 years: 0.9% 6–12 years: 5.9% 13–19 years: 3.7% Refugee (first-generation): 3–5 years: 0.6% 6–12 years: 4.1% 13–19 years: 2.4% Refugee (second-generation): 3–5 years: 1.1% 6–12 years: 6.2% 13–19 years: 3.7%	–	To identify indicators of ADHD diagnoses, implemented adapted criteria used by the Manitoba Centre for Health Policy, which includes a combination of ICD-9-CM and ICD-10 codes from the hospital discharge records and practitioner billing records.	Health administrative records from 1996 to 2016, BC PharmaNet, and Immigration, Refugees, and Citizenship Canada’s (IRCC) Permanent Resident Database.	Male: 51.7% Female: 48.3%	–