Also not a doctor, but from the arm chair research I've done (I have ADHD), in the case of having trauma in childhood it's more likely that those people have PTSD (not ADHD). Certain types of PTSD have overlapping symptoms with ADHD and are commonly misdiagnosed.
Also, people imagine PTSD comes specifically from war, starvation, physical injury, etc. but it actually comes from emotional trauma. Emotional trauma to children can be just as bad from a high conflict or high stress household, even if the family is financially secure.
Having rich parents that fight constantly and emotionally neglect their children is probably emotionally worse than being a homeless war refugee with kind and loving parents... I suspect PTSD is widespread among kids in the middle and upper class, but people categorically deny the possibility of it, and these kids may instead be diagnosed with something else.
The book "Simplicity Parenting" by Kim John Payne was really interesting, because he was actually a psychologist that worked with children in war refugee camps, and later worked with middle class American children from stressful households, and found many of them to be experiencing similar issues, with similar symptoms.
