ADHD is a genetic brain difference - the gene responsible used to be the neuromajority in prehistoric times, i.e. most people had ADHD. (Source: Nature magazine)

People with ADHD have fewer filters and can process a lot of brain messages simultaneously, making sense of incomplete information faster - very useful for a hunter.

The lack of those filters can cause 'traffic jams' in the brain, hence the working memory problems and problems with interoception (brain and body miscommunication - for example, not knowing you are thirsty). Neurotypical people use their own heartbeats as a metronome, having an innate sense of the passage of time; people with ADHD often can't do this ("time blindness").

Other underdeveloped brain areas include those responsible for emotional regulation, hence mood swings, and planning/impulse control. Being more impulsive enables us to be more decisive. Many ADHDers become startup founders, including Microsoft founder Bill Gates.

Children with ADHD receive up to 20,000 more negative messages by the age of 12 than neurotypical children, leading to low self-esteem and rejection sensitivity. This is the compound trauma.

The trauma doesn't cause ADHD.

The trauma isn't part of ADHD.

The trauma is a result of society mistreating people with ADHD.