2026 has been a year for ADHD to be in the spotlight. Many others have commented on pieces in the media which have been spectacularly unhelpful for people with ADHD, so rather than retread those steps, I’m going to focus on the history of ADHD and the differences in the ADHD brain.
Timeline
1775: First mentions of attentional differences in medical literature
1902: George Frederic Still delivers his lectures on children with “defective moral control in association with general impairment of intellect”
1932: Hyperactivity aspect defined by Kramer and Pollnow
1968: Hyperkinetic childhood reaction enters the DSM
1980: Attention Deficit Disorder (ADD) enters the DSM
1987: Renamed as Attention Deficit Hyperactivity Disorder (ADHD)
1994: Split into three subtypes (Hyperactive, Inattentive, Combined)
2008: Adults can be diagnosed with ADHD in the UK
2013: Dual diagnosis of ADHD and autism possible
Causes of ADHD
ADHD is a neurodevelopmental difference in brain development. The prefrontal cortex doesn’t develop to the same degree compared to typically developing brains, and this is where the executive functions are housed.
There are at least 76 known genes associated with ADHD, and it has a degree of heritability of 80%. This means parents with ADHD are likely to have kids with ADHD.
Why the ADHD brain is different
The ADHD brain has a thinner, less developed prefrontal cortex, and different levels of neurotransmitters (most notable dopamine and noradrenaline, associated with reward, movement and motivation).
The executive functions rely on cortical thickness and neurotransmitter levels to develop and to be accessible. When this is different, we will see problems with:
- attention regulation
- ignoring distractions
- doing things differently
- emotional regulation
- risk taking
- decision making
- motivation
- task planning
- task initiation
How is ADHD diagnosed?
Brain scans cannot diagnose ADHD, nor can a GP make a diagnosis. ADHD is diagnosed by psychologist or psychiatrist (only psychiatrists can prescribe medication).
Because the presentation of ADHD is behavioural (as in, it can be seen in the way someone behaves, responds, acts and presents to others) it’s diagnosed by professionals with the knowledge and experience to determine what is seen in typically developing people, and the differences in neurodivergent people. It does not mean that ADHD is a mental health condition!
If you want to learn more about ADHD this October (and the rest of the year – October might be ADHD month but it doesn’t take a day off) get in touch to book an online or in-person training session with me. I’m also an ADHD coach and you can book online coaching with me!