Is ADHD being over-diagnosed and over-treated in Iceland… Or is Iceland simply ahead of the rest?
- Vilhjálmur Hjálmarsson
- Dec 19, 2020
- 9 min read
Updated: 2 days ago
Over the past decade, there has been a lively debate in Iceland regarding ADHD, concerns about over-diagnosis, and the widespread prescription of stimulant medication. Many health professionals and politicians assert that Iceland's statistics significantly exceed those of our Nordic neighbours and, indeed, the rest of Europe. Some even claim that Iceland has surpassed the USA in these areas.
Is this true? Or might Iceland be more like its neighbours on both sides of the Atlantic than commonly believed? Could Iceland be a leader in ADHD diagnoses and medication prescriptions?
“To thine own self be true” – What is the ADHD prevalence in Iceland?
Let’s start by addressing the elephant in the room: Icelandic Directorate of Health hasn’t systematically gathered data on the number of ADHD diagnoses (claiming mainly lack of legal precedence to do so (1). Same goes for exact data on number of medication prescriptions, let alone actual number of individuals who are on stable medication treatment. However, what we do have is an interactive dashboard run by the Directorate of Health in Iceland (2), based on data from health registers and surveys.
This is by no means a perfect base to build from, even if some academic researchers with access to patience journals and other medial data, claim they can pretty much correct for certain errors when using the dashboard data. But it’s all that we currently have at hand.
Keeping the forementioned limitation in mind (3), the raw dashboard dataset states overall number of individuals on stimulant medication (4) (all ages and gender) to be 6,27% of the population, split nearly equally between men and women (women marginally higher in percentage for the first time).
Looking specifically at two age groups, 6-17-year-old children, and adults aged 18 and over (similar groups as used in recent US and Swedish publications that will be introduced later), we see the following:
For the longest time, academics worldwide have frequently referred to general prevalence being as low as 5%-5.5% for children and 2%-2.5% for adults. If that estimate would still hold water, one might say datasets for Iceland are indeed far above that. So, let’s dig a bit further.
If all the world is a stage, what’s the ADHD prevalence?
One frequently used reference in recent academic research is “The World Federation of ADHD International Consensus Statement: 208 Evidence-based conclusions about the disorder (Faraone et al., 2021) (5), where the main conclusion is that ADHD occurs in 5.9 % of youth and 2.5 % of adults.
When this research paper was pointed out to me back in 2023, I found these figures surprisingly low for such a recent publication and began reviewing the sources cited in the paper. In a surprisingly short time, I identified several concerns. Then, after conducting a deeper analysis, I arrived at the following conclusions:
Four out of five key references cited were published between 2010 and 2014, some based on data from two to three decades earlier.
Only one source included data from around 2015–2016, stated to be explicitly limited to the United States-actually, a small segment thereof-making generalization difficult.
In short, the prevalence estimates of “5.9% of youth and 2.5% of adults” appear to be derived primarily from diagnoses and treatment patterns that predate DSM-5, relying instead on DSM-IV-TR, ICD-10, or even earlier diagnostic criteria.
I trust there is no need here, to elaborate on the substantial global impact DSM-5 has had regarding diagnoses and treatment of ADHD, since its release (and later ICD-11).
For the above-mentioned reasons, it seems obvious that by date of publication the 2021 Consensus Statement conclusions was long since outdated (6). This is no laughing matter, since government bodies across Europe are frequently citing the Consensus Statement in policy-making decisions.
When flagging those limitations with the board of The World Federation of ADHD, I highlighted a few more recent sources that directly challenge the claims and data presented in the 2021 International Consensus Statement:
At the CHADD (7) 2024 conference, I came across a recent US CDC study based on 2022 data, which reported the average prevalence of ADHD among children aged 3–17 to be 12.4%. This, along with other recent studies, is discussed on the U.S. Centers for Disease Control and Prevention [CDC] website (8). The CDC notes several important considerations when interpreting their dataset, including that national averages may mask significant variability across states and demographic groups-the range, for example, spans 6% to 16%, with 15% prevalence among boys alone.
Also presented at the same conference was a 2023 CDC study on ADHD among adults (9), which estimated prevalence at 6%. However, as Dr. Thomas E. Brown and others pointed out during their talks, this figure is widely considered to be an underestimation-by roughly one-third. Thus, more accurate prevalence may be closer to 8%.
Additionally, I cited a 2023 study from the Swedish National Board of Health and Welfare (10), which projected that by the end of that year, 15% of boys and 11% of girls aged 10–17 in Sweden would have received an ADHD diagnosis, with 75% of them receiving pharmacological treatment. These numbers directly challenge former claims that Iceland’s prevalence numbers are drastically higher than those of other Nordic countries.
Furthermore, recent media reports and professional interviews from Denmark echo these trends, though I have not yet located formal, peer-reviewed, research papers from Denmark to corroborate that.
While keeping in mind both, the US and Sweden data shows the number of individuals with ADHD diagnoses, but Icelandic data shows the number of individuals having collected their ADHD prescription at least once that year, I still find it quite intriguing how closely the overall numbers match. The same can even be said for each gender group, nearly down to a tee. That alone should warrant a closer look by academic researchers.
Setting aside that aforementioned Swedish and US data looks at the number of diagnoses, while in Iceland we mainly have data based on an individual using a prescription at least once per year, what strikes me is the similarity of the numbers reported. Looking at medication usage specifically, Iceland’s rates across all age groups are only slightly higher than currently reported in the US and Sweden.
It could be said this strongly suggests that either (a) official ADHD prevalence estimates have been significantly underestimated, or (b) ADHD is being substantially overtreated. In my opinion, while both may play a role, overtreatment likely explains only a fraction of the discrepancy. In my mind, that alone warrants a good reason for a deeper comparison than my fleeting attempt.
In September of 2024, four medical doctors in Iceland (psychiatrists and one MD currently completing her doctoral thesis) published a peer-reviewed research article in the Icelandic National Journal of Medicine (Læknablaðið), titled “High prevalence of ADHD medication suggests that ADHD is over diagnosed in Iceland (11).”
In all fairness, it must be stated the research does cover some very interesting aspects, including many of which give good cause for a closer look. However, it’s main flaw lies in their prevalence estimation for Iceland, stating that ADHD occurs in 3.4–7.2% of youth and 2.5–6.8% of adults. Notably, their primary reference for the lower end of these figures was indeed the 2021 International Consensus Statement. The higher end may well come from the one source referenced, relating to prevalence data, that was dated after 2021. Other references were far older than that. This simply undercuts their main conclusion, that number of ADHD diagnosis in Iceland are twice or even three times higher than seen elsewhere.
Is something rotten in the state of Iceland?
In my view, ADHD matters in Iceland are for the most part in good shape. In 2023 The Directorate of Health published revised guidelines on procedures for the diagnosis and treatment of ADHD in children, adolescents and adults (12). This was a much-anticipated change, setting clear guidelines that may very well be among the strictest in our neck of the woods. Perhaps not 100% perfect but work on the next revision has already started.
General awareness among the public is high, thanks in part to the work of The ADHD Association in Iceland (established 1988). Our current membership includes about 1,25% of the population, counting mainly families rather than individual. I could argue our true membership count is closer to 2%. This I believe is quite unique in the world, with only Faroes Island and Jersey being close to that. And interestingly, all three are island nations. Same can be said regarding stigma against stimulant-based medication and ADHD in general. In all my discussions with ministers, leaders of local municipalities, business leaders and the public have shown a great change to the better. I believe some research projects substantiate this, although good references currently escape me for the time being. I have ADHD myself, perhaps I saw a dog and...
But all is not well in the state of Iceland. Persistent underfunding and a predictable decline in the renewal of psychiatric staff have produced the longest healthcare waiting times the world has possibly ever seen. Including both children and adults the current waiting list contains roughly 1.2% of the population. Average waiting time for children and adolescence is +/- 3 years, for adults’ worst-case scenario may be well over a decade. I wonder how Hamlet’s Ofelia would have fared under those circumstances.
Meanwhile a good number of health professionals, academic researchers and politicians claiming we may be largely over-diagnosing and over-treating ADHD with medication. Based on what? I’ve already covered how skewed the ‘currently accepted prevalence percentage’ appears to be, relying mainly on long-outdated facts and data. To my recollection, the loudest naysayers rarely substantiate with any proof, their claim of widespread malpractice among independent psychologists in general. Nor do I recall many psychiatrists losing their medical license based on excessive stimulant-based medication prescriptions, except for a handful proven to be “selling prescriptions.” Those are exceptions, not the rule.
Yes, it is true that in Iceland we are probably diagnosing more individuals with ADHD than our Western European neighbours and North America. Perhaps even, to some extent, in excess. But I challenge any voice claiming ‘in excess’ applies to the masses. I have seen no proof of this being a general problem. Quite on the contrary, the proof more likely seems to boil down to increased awareness and knowledge regarding ADHD and the use of medication. For Iceland, as I see it, the misconception mostly derives from lack of real data and bad interpretation thereof.
Despite the systematic underfunding and ever-increasing waiting time, it can still be said that substantially large numbers of young and old individuals already have their diagnoses and access to medical treatment. Therefore, I’d rather see our government accepting that Iceland could, and perhaps even should, be in the forefront in ADHD diagnoses and treatment. If there are any flaws regarding the diagnoses process, then let’s iron them out. If there are any faults in how psychiatrists decide on ADHD medication, then let’s tackle the reasons behind that.
Let us all embrace the fact that quality-based diagnosing of ADHD can change the life for children, adolescence and adults alike. For me, at the age of 33 years, this became my ground zero platform. A firm ground to stand on and tackle life from a changed perspective.
Let us also embrace the fact that ADHD medication, stimulant based or not, is the most effective treatment available. This is long since supported by multiple research projects and clinical experience. That is not to say that ADHD medication suits everyone or that ADHD medication should be the only choice. Medical treatment, or for that matter any other kind of treatment, should never be the only choice. But for most of us, medication combined with other issues, is for sure a proven way to a better and more meaningful life.
Eventually governments in other countries might even look to Iceland as an example... except perhaps when it comes to lack of support for in-depth research and management of waiting lists for ADHD diagnoses.
“This above all: to thine own self be true”
In my many talks on ADHD and specifically on ADHD medication, I often close with the following:
I have ADHD.
There is nothing wrong with me.
My brain simply works this way, but not the other.
It’s part of me, it’s the way I was born, and I wouldn’t want to be any other way.
But I would have loved to have known and understood somewhat earlier than in my thirties.
Which sort of explains why I constantly choose to take arms against a sea of ADHD misinformation, and by opposing end them (13). □
References
The Icelandic Parliament recently passed amendment to the laws in this regard.
Data only states how many individuals dispense a prescription at least once per year, but neither indicates if that was a one-off incidence nor if an individual is on stable medical treatment.
For simplification I will refer only to stimulant based medication, although 0,5% of the data relates to non-stimulant-based ADHD medication and Modafinil (off-label use for ADHD)
https://www.sciencedirect.com/science/article/pii/S014976342100049X?via%3Dihub
Recently The World Federation of ADHD started the process of revising the Consensus Statement.
Many thanks to my muse and author of Hamlet: William Shakespeare.
