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The Origins of ADHD: When was ADHD Discovered and what Causes ADHD?
Let’s start where it all began for ADHD.
When was ADHD discovered?
ADHD was discovered in the early 1900s in the United Kingdom.
A British pediatrician named Sir George Still first identified ADHD symptoms in 1902. He described the condition as “an abnormal defect of moral control in children.”(1)
He discovered that some affected children were unable to control their behavior compared to other children. He did point out, though, that the affected children’s intelligence was not in question.
Now that we know that ADHD prevalence is not a new condition, where does it come from?
What Causes ADHD?
To this day we still do not know the exact cause of ADHD, but we identified differences between the brains of people with ADHD behavior compared to others.
What this means is that ADHD is caused by factors or mental disorders linked to these brain differences.
It also means that Attention Deficit Hyperactivity Disorder (ADHD) is real. Clinical data is proving that ADHD is not a fake condition made up by the pharmaceutical industry to sell more drugs.
Considering these brain differences are the main perceivable difference between regular people and individuals with ADHD, the terms “ADHD Brains” and “Neurodiversity” are becoming increasingly prevalent in the ADHD community.
Neurodiversity by the way englobes much more than ADHD alone. Conditions like Autism, Tourette, Dyslexia, and others are also linked to brain differences.
There is no strong data on that subject yet, as it is still very new for medical standards, but 30 to 40% of the population is thought to be neuro-diverse. (2)
So brain differences cause ADHD behavior, but why do people with ADHD have different brains?
Is ADHD Hereditary?
We get these questions all the time, Is ADHD genetic? Did I inherit ADHD from my parents?
The short answer is yes, ADHD statistics suggest that ADHD is genetic and that genes responsible for it can be inherited from a parent.
Researchers believe that a gene involved in dopamine production could be linked to ADHD because this chemical regulates the brain and impacts attention span.
Hopefully, we’ll get more clarity soon about the genes behind ADHD!
In our ADHD community, we see countless anecdotal evidence that ADHD does run in families. For instance, after my own ADHD diagnosis, my brother also got diagnosed a few months later.
How ikely are you to pass down ADHD to your Children?
A parent-reported ADHD diagnosis shows that if you have ADHD, your children have approximately a 35% chance of getting it, (3) and that at least one-third of all fathers who had ADHD in their youth have children with the condition. (4)
According to a clinical child and adolescent psychology book, a child with ADHD has a 50% chance of having at least one parent with it too. (5)
Additionally, a large percentage of identical twins share the ADHD trait. (6)
Now that we know the root of ADHD, how common is it?
The Prevalence of ADHD Around the World
How Common is ADHD?
Let’s start in the US where we have the most data.
It is estimated that 9.4% of children and 2.5% of adults in the United States have ADHD, according to the Center for Disease Control (CDC). (7)
That’s 6.1 Million children with ADHD (8) :
-388,000 children between the ages of 2 and 5
-2.4 million children between the ages of 6 and 11
-3.3 million children between the ages of 12 and 17
Want to know which state has the lowest and highest rates of ADHD? Here is the data from the CDC (9) :
States with the lowest rates of ADHD:
New Jersey: 5.5%
States with the highest rates:
Delaware and South Carolina: 11.7%
Once again take this data with a grain of salt, there are a ton of factors that affect the prevalence of ADHD diagnosis at the state level.
I know what you are thinking all of these American stats make you believe that it is an American disorder. That simply isn't the case. The prevalence of ADHD is at least as high among non-US residents, based on an analysis of 50 studies. (10)
ADHD is a common biological disorder that is believed to affect 8% to 12% of the global population. (11)
“Research suggests that the majority of children with ADHD will still have the disorder as adults,” according to Nekeshia Hammond, Psy.D, a specialist on the topic. “One critical thing to do is learn to manage ADHD symptoms, which could positively impact their adult outcomes. Some adults have described experiencing milder impairments in functioning because they have learned triggers and ways to cope with their ADHD symptoms.” (12)
So if ADHD affects 9.4% of children and only 2.5% of adults what does that mean?
Is ADHD over-diagnosed or underdiagnosed?
That means that researchers believe that adult ADHD is very underdiagnosed: “the rate of adult ADHD is likely underreported as 85% of children with ADHD will likely have the disorder as adults.” (13)
It actually makes sense when we think about it, ADHD is a biological disorder based on brain differences. Even though our brains do evolve with age, our genes don’t so the gene(s) responsible for ADHD stay with us all our lives. Our brains likely keep them until we reach adulthood.
It just means that ADHD is not just a childhood disorder. Adults are blinded by this false understanding which explains why most of them don't seek ADHD diagnosis or mental health counseling.
Additionally, the ADHD diagnostic criteria were developed for children, so they do not fit with adulthood ADHD.
The symptoms of mild ADHD can be managed well in some adults that have been diagnosed with it earlier in their lives. Meaning they no longer meet the criteria for ADHD as adults.
“They would not meet the ‘full criteria’ for ADHD (they may still have some of the attention symptoms, but not enough for an official diagnosis),” Dr. Hammond explains. “Most research suggests that ADHD does not really ‘go away,’ but more so that adults report fewer symptoms. For instance, hyperactivity symptoms typically decrease with age.” (14)
So yes, the diagnosis of adult ADHD is significantly underestimated. It is estimated that only 10 to 25 percent of adults with ADHD are diagnosed and appropriately treated. (15)
Is ADHD more common in males or females?
ADHD data shows that men are almost three times more likely to be diagnosed with ADHD than women. (16)
Only 4.2 percent of women are diagnosed with ADHD, compared to 13 percent of men. (17)
So it would appear as if ADHD was a disorder predominantly present in males compared to females. Well not so fast, as we explained earlier how flawed the official diagnosis process can be to diagnose ADHD in adults, researchers believe it is also skewed towards males.
Women are more likely to be diagnosed with a predominantly inattentive presentation, which is often overlooked by doctors compared to the hyperactive presentation most often present in men with ADHD. (18)
Considering the wide variety of ADHD cases (9 official symptoms of inattention & 9 official symptoms of hyperactivity & impulsivity), it makes sense that healthcare professionals issuing diagnoses can have unconscious biases when 2 patients with ADHD could be so different. A great example is the “stereotypical” boy with ADHD running around in the waiting room and the head in the clouds girl with the inattentive presentation of ADHD.
The contrast could not be starker, yet they both have ADHD and could use accommodations to thrive.
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The ADHD Timeline
When does ADHD start?
The first signs of ADHD appear at a young age, usually between 3 and 6 years old. (19) That is what’s universally recognized for the current official diagnosis of moderate ADHD.
ADHD is still a relatively new “disorder” though, and we still have a lot to learn, so a lot might change in the future, like when ADD evolved to become ADHD.
When is ADHD typically diagnosed?
ADHD affects children less than 10 years old. According to the CDC, the average age a patient gets an ADHD diagnosis is 7 years old. (20)
What is interesting to note is that diagnostic timing varies depending on the severity of symptoms. It turns out that usually the earlier the diagnosis, the more severe the disorder (21):
-the average age of diagnosis for children with severe ADHD is 5 years old.
-the average age of diagnosis for children with moderate ADHD is 7 years old.
-the average age of diagnosis for children with mild ADHD is 8 years old.
Are ADHD Diagnoses more frequent now?
Yes the CDC reported a 42% rise in ADHD diagnoses during the past 8 years. (22)
If we look at past ADHD statistics, we see that there has been a steady increase in ADHD diagnoses (23):
-ADHD was diagnosed in 7.8 percent of children in 2003
-ADHD was diagnosed in 9.5 percent of children in 2007
-ADHD was diagnosed in 11 percent of children in 2011
Moreover, ADHD diagnoses among adults are growing four times faster than those among children.
In the United States, we’ve “only” seen a 26.4% increase of ADHD diagnoses among children compared to a 123.3 percent increase among adults. (24)
Critics point to this increase along with the prevalence in the United States compared to other countries to dismiss ADHD.
Our parents and grandparents' generations were not diagnosed with ADHD as much as we are. So now, there is that sentiment that we are sensationalizing something our society seemingly overlooked in the past with no consequence.
Because ADHD is an “invisible illness” and there is so much misinformation on the topic, I understand how it could happen. But the truth is that ADHD is real, and it’s been here all along. We are just better equipped to identify it and deal with it now than we ever have.
That’s what is really at stake here. We know that despite these increases, ADHD is still underdiagnosed and that it should not be dismissed as a condition that can have a major impact on someone’s life. Just ask Simone Biles and how it can derail a life’s work at the Olympics.
ADHD Stats on Treatment
How is ADHD treated?
There is no official cure to ADHD but there is a variety of medication treatment options for patients with ADHD.
ADHD Medication Treatment typically includes cognitive behavioral therapy and talk therapy, but based on a national survey, only 11% of adults with ADHD receive those treatments.
Children are receiving treatment at a much higher rate, 6.1% of all American children are being treated for ADHD with medication. (26)
A study from the CDC reported the following health statistics (27):
Out of a sample of children between 2 and 17 years of age, diagnosed with ADHD:
-62% were taking ADHD medication
-47% received behavioral treatment
-According to the ADHD statistics, the overall treatment rate was 77%.
What age do children with ADHD typically receive treatment?
ADHD statistics from the same CDC study (28) reported the percentage of children by age group that received treatment.
-18% of children with ADHD aged 2 to 5 years old were taking medication.
-69% of children with ADHD aged 6 to 11 years old were taking medication.
-62% of children with ADHD aged 12 to 17 years old were taking medication.
-60% of children diagnosed with ADHD aged 2 to 5 years old were receiving the same treatment.
-51% of children with ADHD aged 6 to 11 years old were receiving behavioral treatment.
-42% of children with ADHD aged 12 to 17 years old were receiving behavioral treatment.
-15% of the children with ADHD aged 2 to 17 years old received behavioral treatment alone.
-30% of the children diagnosed with ADHD aged 2 to 17 years old were treated with medication alone.
-32% of the children with ADHD aged 2 to 17 years old received both behavioral treatment and medication.
-23% of the children with ADHD aged 2 to 17 years old received neither behavioral treatment and medication.
How many children with ADHD also have a learning disorder?
Nearly 45 percent of children with ADHD have some form of learning disorder. (29)
How much does ADHD cost in the US?
$14,576 is the average cost of illness per year for an ADHD patient according to a study from 2007. (30)
How much does ADHD testing cost?
ADHD testing can be expensive, especially in the US. Prices are all over the place as demonstrated by the study that compared ADHD testing prices in Des Moines & Los Angeles. (31):
The minimum price for an ADHD evaluation in Des Moines was $100, versus $375 in Los Angeles.
The maximum price for an ADHD evaluation in Des Moines was $1360, versus $2500 in Los Angeles.
The average price for an ADHD evaluation in Des Moines was $686, versus $1634 in Los Angeles.
The average therapy price per hour for an ADHD evaluation in Des Moines was $128, versus $149 in Los Angeles.
Did you know that people with ADHD are more likely to die prematurely due to an accident?
The life expectancy for people with attention deficit hyperactivity disorder (ADHD) is lower, and they are twice more likely to die prematurely. People with ADHD are more likely to die from accidents than other causes, and women with ADHD are at a much higher risk of dying from accidents than men with ADHD. (38)
ADHD Comorbidity Statistics
How often is ADHD comorbid with other disorders?
ADHD has high rates of comorbidity, especially high psychiatric comorbidity levels. Between 60 and 70% of adults with ADHD have a comorbid disorder. (32)
Where it gets tricky is that comorbid psychiatric disorders may mask the symptoms of ADHD. That contributes to the underdiagnoses of ADHD, because comorbid conditions could be diagnosed instead of ADHD, when ADHD is most likely to be the root cause of the issues.
60% percent of children with ADHD had at least one other mental, emotional, behavioral, or anxiety disorder, according to a national 2016 survey of parents. (33)
What are the most common disorders comorbid with ADHD?
Mood and anxiety disorder, generalized anxiety disorder, substance use disorders (SUD), and personality disorders are among the most common comorbid conditions.
Some adults may go undiagnosed and therefore untreated because of co-occurring mental health conditions that mask the symptoms of ADHD. According to a diagnostical and statistical manual, the most common comorbid disorders for adults with ADHD are (34):
- Anxiety disorders at a 47% rate
- Mood disorders at a 38% rate
- Impulse control at a 20% rate
- Substance abuse disorders at a 15% rate
You read that right, almost half of the patients with ADHD report having anxiety as well!
Children with ADHD also have comorbid conditions (35):
-51.5% of children with ADHD have behavioral or conduct problems
-32.7% have anxiety problems
-16.8% have depression
-13.7% have been diagnosed with autism spectrum disorder (ASD)
-1.2% have Tourette syndrome
Want to know more about ADHD Comorbidity? Check this article now!
ADHD Statistics: FAQs (Frequently Asked Questions)
Can ADHD cause Anxiety?
Yes, ADHD can cause anxiety in fact according to studies about 3 in 10 children with ADHD report symptoms of anxiety. (36)
Is Substance Abuse Disorder linked to ADHD?
ADHD has been reported to be comorbid with substance abuse disorder in up to 27 percent of adolescents, according to a study. (37)
What other disorders are you more likely to have when you have ADHD?
ADHD children are 12 times more likely to develop Loss of Control Eating Syndrome (LOC-ES), an eating disorder similar to binge eating disorder in adults. (38) An individual with ADHD is not at greater risk of developing other diseases or conditions. However people with ADHD, particularly children, are more likely to suffer from a range of coexisting disorders.