Frequency of ADHD (prevalence)

ADHD exists in all cultures and countries worldwide. The frequency of occurrence is called prevalence.

Prevalence can define different terms:
Diagnosis prevalence: Frequency of existing medical diagnoses of a disease in the total population (e.g. within the last 12 months). Dependent on the diagnostic scale and expertise of the person making the diagnosis.
True prevalence / field prevalence / epidemiological prevalence: Frequency of a disease in a thorough examination of a representative group by experts, extrapolated to the total population. This value also depends on the instruments used (for ADHD, for example, higher in DSM 5 than in DSM III).
Treatment prevalence: Prevalence determined on the basis of treatment/prevention contacts. Dependent on the commitment to treatment of people with ADHD.
Administrative prevalence: Prevalence determined from routine statistics (e.g. cancer register). Barely possible for ADHD.

Point prevalence: Number of existing cases at a point in time.
Period prevalence: All cases occurring in a period.

Incidence: Frequency of new diagnoses of a disease in the overall population (e.g. within the last 12 months).

The diagnostic prevalence of ADHD, i.e. the frequency with which practicing doctors and psychologists diagnose ADHD, has risen sharply in recent years as ADHD has become better understood and doctors and psychologists are now better trained. However, the true prevalence, i.e. the frequency with which ADHD actually exists, has not changed. In test studies in which representative groups are examined by specialists, the true prevalence of ADHD remains unchanged.¹

If we use the term prevalence without further explanation, this should in future refer to diagnosis prevalence. As of April 2021, this differentiation has not yet been consistently verified, which is made more difficult by the fact that a number of studies do not formulate this transparently.

• 1. Population prevalence
  • 1.1. Worldwide
  • 1.2. Europe
    • 1.2.1. Germany
    • 1.2.2. Denmark
    • 1.2.3. Finland
    • 1.2.4. France
    • 1.2.5. Czech Republic
    • 1.2.6. Ireland
    • 1.2.7. Iceland
  • 1.3. North America
    • 1.3.1. USA
    • 1.3.2. Canada
  • 1.4. South America
    • 1.4.1. Colombia
  • 1.5. Asia
    • 1.5.1. China
    • 1.5.2. Japan
    • 1.5.3. Taiwan
    • 1.5.4. India
  • 1.6. Africa
    • 1.6.1. Ethiopia
    • 1.6.2. Ghana
    • 1.6.3. Somalia
    • 1.6.4. Mozambique
  • 1.7. Middle East
    • 1.7.1. Iran
    • 1.7.2. Saudi Arabia
    • 1.7.3. Egypt
    • 1.7.4. Jordan
• 2. ADHD prevalence differences by ethnicity
  • 2.1. ADHD prevalence differences by ethnicity in children and adolescents
  • 2.2. ADHD prevalence differences by ethnicity in adults
• 3. Prevalence according to life circumstances
  • 3.1. Prison inmates (11 % to 25 %)
  • 3.2. Refugees and asylum seekers under the age of 18
• 4. Prevalence among psychiatric patients
  • 4.1. Prevalence in outpatient psychiatric populations (17.4% to 23.9%)
  • 4.2. Prevalence in psychiatric clinics (inpatient) (59 %)

1. Population prevalence¶

1.1. Worldwide¶

An overall average prevalence of 5.29% was determined in 2007 from studies conducted between 1978 and 2005.² Few differences were found between North America and Europe, while the figures for Africa and the Middle East differed.
A meta-analysis determined an ADHD prevalence in adults of 3.10 %.³ ADHD-I was more common than ADHD-HI, ADHD-C was the least common.

Children and young people:
A comprehensive study of 13 meta-analyses (588 primary studies with 3,277,590 subjects) determined a worldwide ADHD prevalence in children and adolescents of 8% (boys: 10%, girls: 5%). The most common ADHD subtype was ADHD-I, followed by ADHD-HI and ADHD-C.⁴
in 2018, a study found a prevalence of around 5% in children and adolescents and a further 5% just below the cut-off for a diagnosis.⁵ in 2015, a meta-analysis of 175 studies according to DSM III to DSM IV found a worldwide pooled overall prevalence of ADHD in children and adolescents of 7.2% (6.7% to 7.8%).⁶ in 2012, a meta-analysis of 86 studies with n = 163,688 children and adolescents determined a prevalence of 5.9 % to 7.1 % according to DSM IV⁷

Adults
in 2012, a meta-analysis of 11 studies with n = 14,112 adults determined a prevalence of around 5% according to DSM IV⁷

A study conducted worldwide using the same standardized methods on adults aged 18 to 44 years according to the DSM-IV criteria (aimed at children) found an ADHD prevalence of 2.8% and was higher in high (3.6%) and upper middle (3.0%) income countries than in low/lower middle income countries (1.4%).⁸ We are critical of the design of the study because a pre-selection of subjects was made in a preliminary study. We consider it questionable that adult ADHD should be more common than ADHD in children above the treshold, especially since DSM IV was used as a diagnostic tool tailored to ADHD in children and adolescents.

Country	Prevalence in children (Treshold)	Prevalence in children (Subtreshold)	Prevalence in adults
Belgium	2.9 %	8.6 %	4.1 %
France	4.7 %	8.9 %	7.3 %
Germany	1.8 %	5.6 %	3.1 %
Italy	0.9 %	3.7 %	2.8 %
Netherlands	2.9 %	9.2 %	5.0 %
Northern Ireland	3.2 %	4.5 %	6.0 %
Poland	0.3 %	0.8 %	0.8 %
Portugal	1.5 %	4.0 %	3.0 %
Spain	1.8 %	1.9 %	1.2 %
Spain (Murcia)	2.0 %	4.2 %	3.3 %
USA	8.1 %	6.6 %	5.2 %
Brazil (Sao Paulo)	2.5 %	7.0 %	5.9 %
Colombia (Medellin)	2.5 %	3.0 %	3.0 %
Lebanon	1.5 %	3.3 %	1.8 %
Mexico	3.0 %	3.7 %	1.9 %
Romania	0.4 %	0.7 %	0.6 %
Colombia	1.2 %	2.9 %	2.5 %
Iraq	0.1 %	1.0 %	0.6 %
Peru	0.8 %	2.5 %	1.4 %
China (Shenzen)	0.7 %	3.0 %	1.8 %

The following differences in (diagnostic) prevalence in different regions of the world are likely to represent differences in diagnostic methodology rather than differences in the true prevalence of ADHD.⁹

1.2. Europe¶

1.2.1. Germany¶

The first KiGGS study in 2006 found that just under 5% of children and adolescents in Germany aged between 3 and 17 had already received a medical diagnosis of ADHD (diagnosis prevalence). In addition, a further 5% can be classified as suspected cases ¹⁰
The second KiGGS study from 2017 speaks of 4.4% of children and adolescents who have already received a medical diagnosis.¹¹¹² These are reports from parents or guardians. The statement that an ADHD diagnosis had been made once does not mean that this diagnosis still had to persist at the time of the study survey. It is not the field prevalence (“true prevalence”, study of a randomized group by experts), as the assessment is influenced by the ADHD knowledge of the medical profession. The field prevalence will therefore be higher.

The overall prevalence of ADHD in children and adolescents was found to be 2.2% in the 2007 Bella study¹³ (which we consider to be too low). A Bella sub-study with n= 2500 subjects between the ages of 7 and 17¹⁴ puts the prevalence in the parents’ assessment at around 5%. Both studies confirm a strong divergence in prevalence according to social class. According to the Bella Study 2007, the middle class has the average prevalence, while the lower social class has a prevalence of 3.9%, which is four times higher than the upper class.¹⁵ The Bella sub-study reports a prevalence of ADHD in the lower social class (at 7.2%) that is approximately 2.3 times as high as in the upper class at 2.8% (with 3 strata).¹⁴

In older adults, one study found an ADHD field prevalence of:¹⁶

• 40-59-year-olds: 3.1 %
• 60-80 year olds: 2.1 %
  With regard to current ADHD symptoms, 92.1% of the results of the self-assessment instrument used matched those of the external observation instrument.

Another study found a field prevalence (epidemiological prevalence) in adults of 4.7%.¹⁷
In Germany, 20% of psychiatric and psychotherapeutic patients are said to be affected by ADHD.¹⁸

Further information on the prevalence distribution of ADHD: http://www.adhs.info/fuer-paedagogen/allgemein-stoerungsbild/praevalenzraten.html

1.2.2. Denmark¶

A cohort study in Denmark found a prevalence of 5.9% in boys under 18 years of age according to ICD 10.²¹ Another study of all children born between 1990 and 199 found a prevalence of 3.68%.²²

1.2.3. Finland¶

In Finland, a national cohort study observed an increase in the use of ADHD medication in children from 1.26% in 2008 to 4.42% in 2018 and in adolescents from 0.93% in 2008 to 4.21% in 2018. At the same time, the proportion of women on medication increased.²³
received ADHD treatment with medication in 2019²⁴

• 1.3 % of boys
• 0.48 % of the girls

1.2.4. France¶

The prevalence of ADHD in children aged 6 to 12 was reported to be between 3.5% and 5.6%. Another study gives a value of 0.3%,²⁵ which seems too low.

1.2.5. Czech Republic¶

In a representative cross-section of the population, the diagnostic prevalence in 2019 was 3% and the field prevalence (according to the very simple ASRS) was 7.84%.²⁶

1.2.6. Ireland¶

7,6 %²⁷

1.2.7. Iceland¶

For Iceland, a prescription rate for ADHD medication was reported for 2023 (according to the Icelandic state prescription register) for²⁸
14.7 % of 7- to 17-year-olds (boys 17.7 %, girls 11.6 %)
17.6 % of 12 to 17-year-olds (boys 20.1 %, girls 14.6 %)
10.2 % of 18 to 44-year-old adults (men 9.4 %, women 11.0 %)

The prevalence of diagnosis must therefore be at least as high.

The increase in the prescription rate from 2010 to 2023 amounted to
for 7- to 17-year-olds: 93 % boys, 224 % girls
for 18- to 44-year-olds: 414 % men, 543 % women

As a hypothesis, it is conceivable that immigration countries have a higher rate of ADHD because more impulsive people are more likely to emigrate in times of need.
Iceland was a country of immigration for emigrating Scandinavians, the USA was and is a country of immigration. Both have an above-average prevalence of ADHD.
This hypothesis should be accompanied by a mirror image of reduced ADHD rates in emigration countries. At least for Ireland, this does not appear to be the case.

1.3. North America¶

1.3.1. USA¶

In the US, the incidence of diagnosis of all developmental disorders, including ADHD, has increased significantly from 2009 to 2018:²⁹³⁰³¹

By age:

• Adults: 14.6 % (DSM 5)³²
• Children
  • Children aged 3 to 17 with a diagnosis of ADHD (diagnosis prevalence)
    • 2010: 8 %
    • 2017: 8.5 % to 9.5 %²⁹
    • 2018: 9,8 %
    • 2020 to 2022: 11.3 %³³
    • Boys
      • 2010: 11 %
      • 2018: 13 %
      • 1997 to 2018: 12.93 %³⁴
      • 2020 to 2022: 14.5 %³³
    • Girls
      • 2010: 6 %
      • 2018: 6,6 %
      • 1997 to 2018: 5.61 %³⁴
      • 2020 to 2022: 8.0 %³³
      • Black girls aged 7 to 17: 6.4% to 9.2%; the inattentive subtype was most common³⁵
      • White girls between 7 and 17 years: 2.3% to 6.4%; the inattentive subtype was most common³⁵
    • By age
      • 3-4: Learning disability 3.2%, ADHD 1.2% (2018)
      • 5-9: ADHDS 6.57 % (1997-2018)³⁴
      • 5-11: Learning disability 6.7 %, ADHD 9 % (2018)
      • 12-17: Learning disability 9.4%, ADHD 13.6% (2018)
      • 10-17: ADHD 11.09 % (1997-2018)³⁴
  • Children aged 4 to 17 in a nationwide telephone survey (diagnosis prevalence)³⁶
    • 2003: 7,8 %
    • 2007: 9.5 %; 4.8 % taking ADHD medication
    • 2019/2020: 8,5 %³⁷
  • Children aged 5 to 11 in California (diagnosis prevalence)³⁸
    • 2001: 2,1 %
    • 2010: 3,1 %

By ethnicity:

• Hispanic children (2010: 4 %; 2018: 6.9 %)³⁹

• non-Hispanic white children (2010: 10 %; 2018: 10.9 %)³⁹

• non-Hispanic black children (2010: 11 %; 2018: 13.1 %) Children³⁹

• Children of couples with one white and one Native American parent (American Indian / Alaska Native) 2018: 26.4 %³⁹

• People who identify as two or more races: ADHDS 12.36% (1997-2018)³⁴

• Whites: ADHD 9.83% (1997-2018)³⁴

• Blacks/African Americans: ADHD 10.09% (1997-2018)³⁴

• Hispanic/Latino: ADHD 5.36% (1997-2018)³⁴

• Non-Hispanic/Latino: ADHD 10.64% (1997-2018)³⁴

• Below the poverty line: ADHD 11.41 % (1997-2018)³⁴

• Income from 100 to 199 % of the poverty line: ADHD 10.6 % (1997-2018)³⁴

• Income from 200 to 399 % of the poverty line: ADHD 8.6 % (1997-2018)³⁴

• Income of 400% or more of the poverty line: ADHD 8.39% (1997-2018)³⁴

• Medicaid recipients: ADHD 12.57% (1997-2018)³⁴

• Privately insured: ADHD 9.65 % (1997-2018)³⁴

• Insured persons: ADHD 8.11 % (1997-2018)³⁴

• Uninsured: ADHD 5.83 % (1997-2018)³⁴

Children of single mothers were around twice as likely to have learning difficulties (2010: 12%; 2018: 11.3%) or ADHD (2010: 13%; 2018: 12.6%) as children in families with two parents (learning difficulties 2010: 6%, 2018: 5.9%; ADHD 2010: 7%, 2018: 8.8%). In 2018, only 5% of children of single fathers had learning difficulties and 6.7% had ADHD.
Children with average or poor health were around five times as likely to have a learning disability (2010: 28% to 6%; 2018: 32.3% to 5.9%) and around twice as likely to have ADHD (2010: 18% to 7%; 2018: 16.2% to 8.8%) as children with excellent or very good health. At 15.4%, ADHD was barely more common among children in good health in 2018 than among those in average or poor health.
Children in cities with over 1 million inhabitants were less likely to be diagnosed with ADHD in 2018 (8.2%) than children in cities with less than 1 million inhabitants (12%) or outside of large cities (11.6%).
Between 2009 and 2016, an increase in the annual prevalence of ADHD of around 250% from 0.23% to 0.84% was observed in war veterans.³⁹
Friedmann reports that the lifetime prevalence of ADHD in the USA has risen from 7.8% in 2003 to 11% in 2011.⁴⁰ This is not due to an increase in ADHD (true prevalence), but to the fact that ADHD is now better recognized and more reliably diagnosed (diagnostic prevalence).

A 20-year study from 1997 to 2016 in the USA found diagnosis prevalence in children and adolescents:⁴¹

• 6.1 % in 1997/1998
• 10.2 % in 2015/2016, of which
  • Boys 14.0 %
  • Girls 6.3 %
  • hispanic 6.1 %
  • non-Hispanic white 12.0 %
  • non-Hispanic black 12.8 %

The increase in diagnosis prevalence is likely explained by the improved diagnosis of ADHD. The true prevalence of ADHD in children in the USA did not change between 2003 and 2007.⁹

One study found very different ADHD prevalences by county. The data was collected through parental reports, which severely impairs its validity:⁴²
USA national: 12.9 % (11.5 % to 14.4 %)
Areas with a high prevalence of ADHD:

• West South Central: 55.1% of counties had a prevalence of 16% or more
• East South Central: 53.6% of counties had a prevalence of 16% or more
• New England: 49.3% of counties had a prevalence of 16% or more
• South Atlantic: 46.2% of counties had a prevalence of 16% or more
  Areas with a low prevalence of ADHD:
• East North Central: 11.7% of counties had a prevalence of 16% or more
• Pacific: 6.9% of counties had a prevalence of 16% or more
• West North Central: 5.8% of counties had a prevalence of 16% or more
• Mid Atlantic: 4% of counties had a prevalence of 16% or more
• Mountain: 2.1% of counties had a prevalence of 16% or more

1.3.2. Canada¶

Canadian children diagnosed with ADHD were⁴³

• Girls
  • 2008: 3,1 %
  • 2015: 3,9 %
• Boys:
  • 2008: 8 %
  • 2015: 9,5 %

In contrast, the calculated true prevalence was⁴⁴

• 4 - 17 years
  • 2008: 6,92 %
    • Girls: 6.0 %
    • Boys: 7.9 %
  • 2015: 8,57 %
    • Girls: 6.5 %
    • Boys: 10.1 %
• 18 - 34 years
  • 2008: 5,73 %
    • Women: 5.4 %
    • Men: 6.2 %
  • 2015: 7,33 %
    • Women: 6.3 %
    • Men: 8.6 %
• 35 - 64 years
  • 2008: 5,20 %
    • Women: 5.2 %
    • Men: 5.3 %
  • 2015: 5,54 %
    • Women: 5.4 %
    • Men: 5.7 %

1.4. South America¶

1.4.1. Colombia¶

One study found an ADHD prevalence of 16.4% among Paisa children in Colombia (boys 19.8%, girls 12.3%).⁴⁵

1.5. Asia¶

East Asian (N = 1301) and South Asian (N = 730) adolescents were significantly less likely to have an ADHD diagnosis than White adolescents:⁴⁶

• East Asian adolescents: OR = 0.16
• South Asian adolescents: OR = 0.45

1.5.1. China¶

In China, a prevalence of 6.26% was found in children and adolescents (63 studies from 1983 to 2015, 70% of which were conducted between 2005 and 2015), with significant regional differences.⁴⁷

1.5.2. Japan¶

Among Japanese adults, the prevalence of ADHD is said to be 1.7%.⁴⁸

Among Japanese female students (∅ 19.2 years), ADHD-HI was found in 27.2% and ADHD-I in 1.1%.⁴⁹ Another study reported 27% ADHD in Japanese students (29.7% males, 25.3% females).⁵⁰

One study reported 31.1% ADHD by parent report (n = 7,566) and 4.3% ADHD by teacher report (n = 9,9 56) with an overall prevalence of 7.2 to 7.9% among Japanese preschool children. It is possible that parental reports in Japan are not reliable for cultural reasons.⁵¹ Another study also found evidence of excessive parental ratings for young children in Japan.⁵² While the parents of 4 to 12-year-olds identified an ADHD rate of 7.7%, the children’s teacher ratings revealed ADHD in only 3.19% (according to DSM III).

1.5.3. Taiwan¶

A large study found an increase in new ICD 9 ADHD diagnoses from 7.92/10000 person-years in 2000 to 13.92/10000 person-years in 2011, with the male to female ratio decreasing from 3.61 to 2.90. The largest increase was found in young adults (19-30 years), followed by preschoolers (0-6 years).⁵³

1.5.4. India¶

A large study put the prevalence of ADHD in India in 2017 at 0.3%.⁵⁴ The prevalence of ASD was put at 3.2%.

In a rural area of northern India, a prevalence of AD⁵⁵

1.6. Africa¶

A meta-analysis of 63 studies with n = 849,902 participants found a mean prevalence of 10.3% for the Middle East and North Africa.⁵⁶

1.6.1. Ethiopia¶

In Ethiopia in 2022, a study of children and adolescents aged 6 to 17 years found a field prevalence of 13%.⁵⁷ in 2015, a study of 6 to 17-year-olds found a prevalence of 7.3%. There were 80% more boys than girls affected, children of single parents were 5 times more likely to be affected and children from families with a low socio-economic status were 2.4 times more likely to be affected.⁵⁸ Another study found a field prevalence of 9.9%⁵⁹
A meta-analysis found an overall pooled prevalence in children and adolescents of 14.2%. Risk factors were: Male (OR: 2.19), aged 6-11 years (OR: 3.67), low family socioeconomic status (OR: 3.45), maternal complications during pregnancy (OR: 3.29) and a family history of mental illness (OR: 3.83).⁶⁰

1.6.2. Ghana¶

A study in Ghana in 2016 found a prevalence of 1.64% among children aged 7 to 15.⁶¹

1.6.3. Somalia¶

A study in Somalia found a prevalence of 2.8% in children aged 7 to 15.⁶²

1.6.4. Mozambique¶

An ADHD prevalence of 13.4% was found among primary school pupils in Mozambique. Using stricter standards, the prevalence was 6.7%.⁶³

1.7. Middle East¶

A meta-analysis of 63 studies with n = 849,902 participants found a mean prevalence of 10.3% for the Middle East and North Africa.⁵⁶ The prevalence in children and adolescents (59 studies) was 10.1 %, the prevalence in adults (4 studies) was 13.5 %.

1.7.1. Iran¶

A meta-analysis of 19 studies found a mean prevalence of 14.8% for Iran.⁵⁶

In Iran, a study published in 2019 found a prevalence of 4% (5.2% in boys, 2.7% in girls) between the ages of 6 and 18.⁶⁴

1.7.2. Saudi Arabia¶

A meta-analysis of 14 studies with n = 455,334 persons with ADHD found an ADHD prevalence of 12.4% in the Saudi population as a whole⁶⁵
A meta-analysis of 8 studies found a mean prevalence of 13.5% for Saudi Arabia.⁵⁶

A study of 2280 students from 11 colleges at King Abdulaziz University, one of the largest universities in Saudi Arabia, were personally assessed with a validated Arabic version of the Adult ADHD Self-Report Scale. Of the 2059 students (90%) who completed the questionnaire (mean age: 21.2 years), 11.9% met the criteria for adult ADHD. Only 6.5% had been diagnosed with ADHD in childhood and only 0.8% had taken medication for it.
This is one of the few studies on the true prevalence (field prevalence) of ADHD.⁶⁶
The risk of ADHD correlated with

• high family income
• poor grades in the last semester
• Divorce of the parents
• ADHD diagnosis in childhood
• previous diagnosis of depression
• higher severity of current depression and anxiety
• Smoking cigarettes.

A study of 200 randomly selected medical students found an ADHD prevalence of 33.3% using the ASRS. Women, third-year students and the 21- to 26-year-old age group were the high-risk groups for ADHD.⁶⁷ However, the ASRS is a screening instrument and therefore not very suitable for measuring prevalence.

A study of adults aged 21 to 30 (77 women) reported ADHD symptoms in 48%⁶⁸
A study of young adults reported an ADHD prevalence of 34.7% using the ASRS.⁶⁹

The increased prevalence of ADHD in the Arab region could be related to the high rate of marriages between blood relatives on the Arabian Peninsula (Saudi Arabia: 52%).⁷⁰

1.7.3. Egypt¶

A meta-analysis of 9 studies found a mean prevalence of 13.3% for Egypt.⁵⁶

The prevalence of ADHD in preschool children (3 to 6 years) was 10.5%. ADHD-I was the most common (5.3 %), followed by the hyperactivity form (3.4 %).⁷¹
The risk of ADHD correlated with

• positive family history of psychological and neurological symptoms (17.9% positive vs. 9.7% negative)
• Family history of ADHD symptoms (24.5% positive vs. 9.4% negative)
• active smoking of the mother (21.1 % positive vs. 5.3 % negative)
• Delivery by caesarean section (66.4 % positive vs. 53.9 % negative)
• increased blood pressure during pregnancy (19.1 % positive vs. 12.4 % negative)
• Drug use during pregnancy (43.6% positive vs. 31.7% negative)
  Significant risk factors for children were:
• Lead exposure (25.5% positive compared to 12.3% negative)
• Children with heart problems (38.2% positive compared to 16.6% negative)
• Hours a child spent in front of the TV or cell phone (any screen) per day (60.0% of children who tested positive spent more than 2 hours per day compared to 45.7% negative).

The prevalence of ADHD in medical students was 11.0%.⁷²

1.7.4. Jordan¶

A meta-analysis of 2 studies found a mean prevalence of 23.4% for Jordan (one study with 40.6%, one study 6.2%).⁵⁶

2. ADHD prevalence differences by ethnicity¶

The prevalence of ADHD apparently differs between different ethnic groups.
As ADHD is largely genetic, a different prevalence between different ethnic groups would not be surprising. In our opinion, these differences cannot be explained solely by differences in cultural tolerance for externalizing symptoms and the frequency of health insurance.

2.1. ADHD prevalence differences by ethnicity in children and adolescents¶

• Whites: 16.8 % (meta-analysis, n = 835,505 subjects, k = 25 studies)⁷⁴
• Blacks: 15.9 % (meta-analysis, n = 218,445, k = 26 )⁷⁴
• Asians: 12.4 % (meta-analysis, n = 66,413, k = 7)⁷⁴
• Latin Americans: 10.1 % (meta-analysis, n = 493,417, k = 24)⁷⁴

A cohort study of Scottish schoolchildren examined the relative prevalence distribution by ethnicity. 100 % would be an even distribution. Asians and blacks therefore had significantly less ADHD than would have been expected based on the proportion of subjects⁷⁵

• Whites: 102.8 %
• Other: 100 %
• Mixed: 55.6 %
• Colored: 33.3 %
• Asians: 8.3 %

An American cohort study (n = 17,100) found⁷⁶

• Whiteness 100 % (comparative value)
• African-Americans: 69 %
• Hispanic: 50 %
• Other ethnicities: 46 %

Children without health insurance were diagnosed less frequently. Whites were more likely to receive prescription medication for a diagnosed ADHD.

An American multicenter study (n = 4,297) found:⁷⁷

• Whiteness 100 % (comparative value)
• African-Americans: 40 % - 42 %
• Hispanic: 37 %

The frequency of medication use in the case of an ADHD diagnosis was slightly lower in white children.

2.2. ADHD prevalence differences by ethnicity in adults¶

Frequency of diagnoses given within a year to patients who use a specific medical record system⁷⁸. This is not the lifetime prevalence. Study, n = 5.2 million:⁷⁹

• Whites: 0.67 - 1.42 %
• Indigenous people: 0.56 %-1.14 %
• Hispanic or Latino: 0.25 %-0.65 %
• Colored: 0.22 %-0.69 %
• Asian-American persons: 0.11 %-0.35 %
• Pacific Islanders: 0.11 %-0.39 %
• Individuals of other ethnicities: 0.29 %-0.71 %

3. Prevalence according to life circumstances¶

3.1. Prison inmates (11 % to 25 %)¶

Field prevalence is determined by examinations of a representative group of test persons by specialists and is to be distinguished from treatment prevalence (diagnosis prevalence), which measures the frequency of existing diagnoses on the part of the normal medical profession and therefore also measures their level of knowledge.

• 54.4 % lifetime prevalence of ADHD in Spanish prison inmates⁸⁰ with an acute prevalence of 16.4 %. The lifetime prevalence of an Axis 1 Disorder was 81.4 %.
• 25% ADHD field prevalence (“true prevalence”) among adult prison inmates in the UK⁸¹
• 22.2 % ADHD field prevalence in adult prisons (meta-analysis, k = 28, n = 7,710)⁸²
• 17% ADHD field prevalence in Canada (determined with stricter diagnostic criteria)⁸³
• 16.4% acute ADHD prevalence among Spanish prison inmates⁸⁰
• 11 % ADHD field prevalence in France (determined with stricter diagnostic criteria)⁸³
• 8.3 % ADHD field prevalence in adult prisons (meta-analysis, k = 11, n = 3,919)⁸⁴; was criticized by another meta-analysis that determined a prevalence of 22.2 % by extending the data used.⁸²

3.2. Refugees and asylum seekers under the age of 18¶

Among refugees and asylum seekers under the age of 18, ADHD prevalence was found to be 8.6% (1 to 16%), while PTSD (22.71%), anxiety disorders (15.77%), depression (13.81%) and ODD (1.77%) were also found (meta-analysis, k = 8, n = 779).⁸⁵ In our opinion, the high levels of PTSD, anxiety disorders and depression may have masked the actual prevalence of ADHD in the target group studied.

4. Prevalence among psychiatric patients¶

4.1. Prevalence in outpatient psychiatric populations (17.4% to 23.9%)¶

Prevalence rates of were found among people undergoing outpatient psychiatric treatment

• 14.7 to 26.1 % in adult patients of outpatient treatment centers (meta-analysis, k = 14, n = 9,444)⁸⁶
• 23.9% in France (using the ASRS, which tends to overestimate prevalence as a screening tool)⁸⁷
• 22% in the UK (ASRS and WURS).⁸⁸
• 21 % in Sweden (WURS)⁸⁹
• 17.4 % in Europe (DIVA, DSM 5 criteria)⁹⁰

4.2. Prevalence in psychiatric clinics (inpatient) (59 %)¶

In adult inpatients at a German psychiatric clinic, 59% were diagnosed with ADHD (12-month prevalence).⁹¹