Welcome to ADHD. Maybe you’ve met before, but in case you’ve forgotten its name, it stands for Attention Deficit Hyperactivity Disorder. People diagnosed with ADHD report commonly forgetting people’s names, but that’s really just the tip of the iceberg when it comes to understanding the condition.
A lot of people think they know what ADHD is. Ritalin has been dosed out to hyperactive boys since the 1960s in the US, and the 90s saw a huge rise in diagnosis and prescriptions. The funny thing is, we only started being able to scan brains-in-action properly after the fMRI was developed in 1991.
Since then, techniques and technology have become a lot better, but they’re still in their infancy. In 2021, a one-millionth slice of a brain was scanned in high resolution and made available. The file is 1.4 petabytes (1024 gigabytes to the terabyte, 1024 terabytes to the petabyte) and, again, the whole rest of the brain is literally a million times the size.
All of this to say that the time is ripe to update our idea of what ADHD is and how it affects people.
What does science tell us about ADHD?
Neuroscientists tell us that it is primarily a disorder of delayed brain development in some very specific brain regions. Specifically, the frontal lobe, and even more specifically, the prefrontal cortex.
When you compare our human brains to any other species on the planet, the single most unique bit about us is our prefrontal cortex - it’s bigger, more complex in its wiring, and eats way more energy (and is therefore more active) than the prefrontal cortex of any other life form. That’s the bit that ADHD people are slower to develop, and the lack of it is where a lot of the symptoms seem to be coming from.
The prefrontal cortex is the bit of the brain that lights up in brain scanners when you suppress an impulse, particularly if it’s in favour of long term goals. It down-regulates the entire limbic system of the brain (which is associated with feeling emotion, fear, and aggression). It also links to working memory - the ability to mentally hold onto what you were just doing before you were interrupted.
The epigenetic link to ADHD
Researchers now understand ADHD as primarily a condition impacting self-regulation. While it was once considered a straight genetic condition, the notion that there is one gene responsible for ADHD which can be isolated and ‘fixed’ is outdated. The newest scientific studies are finding a strong and promising link to the role epigenetics plays in the development of ADHD.
In a nutshell, epigenetics is the study of the environmental and psychological impact on genetic expression. Its findings show we are born with genetic predispositions, but there are environmental factors such as family of origin, stress, adversity and trauma that impact how the genetic components of those genes are expressed.
With a smaller prefrontal cortex, ADHD people typically show less impulse control, are more emotionally reactive, and struggle to maintain attention on complex tasks. These broad symptoms have many different expressions in work, home and life, and for an adult to be diagnosed with ADHD, these symptoms must have been present since childhood. Some symptoms may disappear or reduce in intensity with maturity.
This, of course, depends on the kind of ADHD you have.
There are 3 types of ADHD
Science has now identified that ADHD individuals typically present a cluster of symptoms in one of three categories:
- Predominantly hyperactive/impulsive
- Predominantly inattentive
- Combined
Check out this article for a list of symptoms in adults.