I do think the field of psychopharmacology is probably sufficient to give an appreciation of the complexity involved at the same time as being useful to the pra

I do think the field of psychopharmacology is probably sufficient to give an appreciation of the complexity involved at the same time as being useful to the practical understanding of how medications (and food) change behavior. It's also well studied and there are good books. I think Dr Stahl's books are the university standard. Like a lot of science though I think much of it is 'current best guess'. For information on the modifying DNA expression in neurons that's under epigenetics and not as well studied.