Is ADHD under- or over-diagnosed?
The number of ADHD diagnoses has risen significantly in recent decades. However, this says nothing about whether ADHD is under- or overdiagnosed.
ADHD has become much better known in recent years. The fact that ADHD also affects adults became apparent in research at around the turn of the millennium. Naturally, it took several years for this realization to reach clinical practice, i.e. doctors and psychologists.
Since 2022, social media (Instagram, TikTok, Facebook) have brought the issue to the public’s attention in an entertaining way.
1. Underdiagnosis of ADHD
Our impression is that many adult people with ADHD only realize through social media what has been bothering them all their lives and that this burden does not necessarily have to be simply accepted. This leads to an increasing demand for diagnostics.
In German-speaking countries, many doctors and psychologists are not yet familiar with ADHD in adults to the extent that would be appropriate for a disorder that affects 8 to 12% of all children1 and 5 to 8% of all adults. However, we are seeing that more and more doctors and psychologists are recognizing the problem and that there are now a growing number of doctors and psychologists beyond the renowned specialists who are excellently informed about ADHD and are also very good at solving difficult problems.
A meta-analysis of 135 studies found no evidence that the prevalence of ADHD has changed in the last three decades. Differences in prevalence are rather the result of different study methods.2
Differences naturally arise if one looks at the diagnostic prevalence (how often ADHD is present in the population when a representative group of specialists is examined) instead of the field prevalence (how often ADHD has been diagnosed). The diagnostic prevalence depends firstly on the awareness of people with ADHD (which prompts them to seek a diagnosis) and secondly on the knowledge of the medical profession (the ability to recognize ADHD). Both have grown significantly in recent years, leading to an increase in ADHD diagnoses.
Furthermore, the relevant data do not indicate that ADHD is diagnosed too frequently or too rarely.3
A Japanese population study of 2,945 participants found 91 people with ADHD, 76 of whom were previously undiagnosed. The study describes the considerable burden on people with ADHD.4
Children with subclinical ADHD (ADHD that is too severe for a diagnosis) have impaired social functioning and comorbidities and increased body fat to the same extent as children with diagnosed ADHD.5 This suggests too high rather than too low thresholds for an ADHD diagnosis.
2. Under-treatment of ADHD
Around 3/4 of all children with ADHD receive no treatment.6
It is sometimes mentioned that the consumption of methylphenidate (the main ADHD drug) is measured in tons. This is correct.
With adequate knowledge and use of basic arithmetic, the amount of MPH consumption is clear evidence of undertreatment.
In Germany, around 1.8 tons of methylphenidate were prescribed and consumed in 2013.
1 ton is 1000 kg is 1000 x 1000 = 1 million grams.
The average daily dose is 40 mg.
The annual requirement of a person with ADHD is therefore 365 x 40 = 14,600 milligrams = 14.6 grams.
1 million / 14.6 equals 68,493 annual doses. this means that 1 tonne of MPH is enough to treat 68,493 people with ADHD for a year.
1.8 tons / year is enough for around 123,000 people with ADHD / year.
In 2019, a total of around 56 million daily doses of methylphenidate were prescribed by German doctors.7
This corresponds to around 153,000 annual doses, an increase of around 25 % compared to 2013.
Of Germany’s 82 million inhabitants, 46 million are adults of working age.
If 6% of these are affected, this results in 4.92 million people with ADHD.
The 1.8 tons mentioned are therefore sufficient for 2.51% of the people with ADHD in employment.
But then no child or adult outside of working age has received MPH.
This shows that there is very severe under-treatment.
A study reports a medication rate of8 from the various regions of Scotland for 2019
- 4 % to 59 % of young people and
- 0 % to 15 % of adults
Regan SL, Williams MT, Vorhees CV (2022): Review of rodent models of attention deficit hyperactivity disorder. Neurosci Biobehav Rev. 2022 Jan;132:621-637. doi: 10.1016/j.neubiorev.2021.11.041. PMID: 34848247; PMCID: PMC8816876.) ↥
Polanczyk GV, Willcutt EG, Salum GA, Kieling C, Rohde LA (2014): ADHD prevalence estimates across three decades: an updated systematic review and meta-regression analysis. Int J Epidemiol. 2014 Apr;43(2):434-42. doi: 10.1093/ije/dyt261. PMID: 24464188; PMCID: PMC4817588. METASTUDIE ↥
Sciutto MJ, Eisenberg M (2007): Evaluating the evidence for and against the overdiagnosis of ADHD. J Atten Disord. 2007 Sep;11(2):106-13. doi: 10.1177/1087054707300094. PMID: 17709814. REVIEW ↥
Okumura Y, Yamasaki S, Ando S, Usami M, Endo K, Hiraiwa-Hasegawa M, Kasai K, Nishida A (2021): Psychosocial Burden of Undiagnosed Persistent ADHD Symptoms in 12-Year-Old Children: A Population-Based Birth Cohort Study. J Atten Disord. 2021 Mar;25(5):636-645. doi: 10.1177/1087054719837746. PMID: 30924712. ↥
He L, Zhao Y, Gong JX, Zhao L, Ma ZR, Xiong QW, Cai SZ, Yan XM (2024): Contrasting presentations of children with ADHD and subthreshold ADHD. Pediatr Res. 2024 Aug 24. doi: 10.1038/s41390-024-03502-y. PMID: 39179877. ↥
Olfson M, Wall MM, Wang S, Laje G, Blanco C. Treatment of US Children With Attention-Deficit/Hyperactivity Disorder in the Adolescent Brain Cognitive Development Study. JAMA Netw Open. 2023 Apr 3;6(4):e2310999. doi: 10.1001/jamanetworkopen.2023.10999. PMID: 37115542. n = 11. ↥
Statista: Anzahl der Verordnungen von Methylphenidat, Atomoxetin und Lisdexamfetamin in Deutschland in den Jahren von 2004 bis 2020 ↥
Radley A, Melia B, Maciver D, Rutherford M, Boilson M (2024): An analysis of prescribing data in attention-deficit hyperactivity disorder for adolescents and adults in Scotland. BJPsych Open. 2024 Aug 8;10(5):e143. doi: 10.1192/bjo.2024.722. PMID: 39113462. ↥