Hi, @senseicat.
Try looking at chinese medicine. At least have a consultation. Chinese medicine understands the body in a more holistic sense.
It's basis is the yin and yang theory.
Yang is the active force.
Yin is the receptive form.
Yin and yang are two opposite enrgies that exist within us. When they are in balance there is synergy and our body and mind function optimally and efficiently.
When yin and yang are out of balance diseases and illness can set in.
In the case of ADHD there is too much Yang (hyperactive energy) and not enough Yin (receptive listening, attention, learning, absorbing and concentration).
So the key to solving the problem would be to reduce the excess yang and increase the deficient yin. How to do it? I personally don't know but a traditional chinese medicine practitioner could.
The video that explains the theory of yin and yang starts at 7 min mark.