We have a situation where the school resource officer has reason to believe that a child's parent is using the child's A.D.D. medicine. Is there a criminal offense?

Look at CSA Sec 481.129 (a) (5) (A)

Misrepresenting to medical personnel that medication is for the child when it is for the adult.

Would probably need search warrant for blood draw on parent to show they consumed the child's medication.

Also, look at Sec. 481.140 Use of Child in Commission of Offense, which enhances the punishment.