Can a Mature Minor Refuse Medical Treatment

[Dogmatique]

So is there any case law regarding this issue?

Nexis, Westlaw, Google Scholar ... those are places to start looking.

[Mr. Knowitall]

So is there any case law regarding this issue?

Case law regarding what issue? For there to be case law, a case must be appealed from a trial court decision and the Court of Appeals must deem their resulting decision to be worthy of publication. I suspect that you can count the number of cases where a minor sued his parents over ADHD medication, then appealed a verdict requiring him to take the medication with the appellate court publishing the decision, on zero hands.