You can Google ADHD and probiotics and see some interesting thing. I've heard from doctors who use probiotics before anythings else.
That reminds me that a recent study found potential links between "gut flora" and depression. Probiotics are needed to synthesis all sorts of things
Gut bacteria may have impact on mental health, study says
Research opens door to possible treatments for depression based on probiotics
https://www.theguardian.com/science/...pression-study