ADHD – genetics or an evolutionary mismatch

Daniel Michael Msc. Applied Psych.

Firstly, for the uninitiated, ADHD stands for Attention Deficit Hyperactivity Disorder. The cause of ADHD is unknown, but there are numerous studies that suggest that genetics plays a significant role. These studies show that it is a brain based biological disorder, and through the use of PET (positron emission tomography) scans it has been determined that brain metabolism in those with ADHD is lower in areas governing movement, attention, and social judgement. Some of the main symptoms associated with ADHD are as follows:

Inattention:

1. Short attention span

2. Difficulty attending to details

3. Easily distracted

4. Difficulty listening to others

5. Forgetful

6. Poor organizational skills

Impulsivity:

1. Often interrupts others

2. Has difficulty waiting

3. Tendency to finish other sentences or blurt out answers

4. Often acts without thinking

Hyperactivity:

1. Constantly moving, often with no purpose to the movement

2. Has difficulty remaining stationary for extended periods

3. Fidgets excessively

4. Talks excessively

5. Has difficulty engaging in quiet activities

6. Loses or forgets things repeatedly

7. Inability to stay on task

It is worth noting that many of these symptoms are just as likely to present themselves in those who do not have ADHD, as they are not exclusive to those suffering from this disorder.

Aside from studies linking genetics to ADHD, some believe ADHD to be a residual evolutionary trait carried over from a bygone era, in which current environmental demands no longer require such spread attention and alertness. This is termed as an ‘evolutionary mismatch’ (Cofnas, 2016). This evolutionary mismatch postulates that at some point in our evolutionary journey, traits from ADHD, if not all then some, were beneficial for our ancestor’s survival; however, we can’t be certain which of these traits would have the desired affects, as again, it is largely dependent on the environment. As a result of our modern environment, the traits linked with ADHD are no longer desirable, much like how humans evolved to survive during times of food scarcity by eating high calorie foods when available; now in an environment where food is generally plentiful, this previously lifesaving train now contributes to widespread obesity.

This evolutionary perspective, that pushes the thought that there is a disconnect between our current environment and our physiological and mental predispositions helps to try change the perception that those with ADHD are being naughty or negligent, but rather are caught in an evolutionary mismatch.

It is uncertain where ADHD stems from, but regardless it is something we know affects many at present, and sometimes perspective will not just alter how those with ADHD are viewed by others, but also how they perceive themselves.

References: Cofnas, N (2016) A teleofunctional account of evolutionary mismatch. Biological Philosophy, 31: 507–25.Google Scholar

Jay N. Giedd (2019) The Enigma of Neuroimaging in ADHD. American Journal of Psychiatry, 176:7, 503-504