Neurotransmitter imbalances, like dopamine in the prefrontal cortex, can live downstream from copper challenges. Too much or too little copper can create psychiatric challenges only correctable if identified.
If you think you have it bad with ADHD, just throw picky eating into the problem. Then ADHD can become almost untreatable. Those with picky eating problems often [not always!] have significant problems with the North of the GI tract and immunity which gums up the works.