CBD is legal in TN, but may not be prescribed or recommended by a physician or vet.
I am most familiar with veterinary CBD use and have bought some for arthritis treatment in my very elderly Akita but haven't yet seen the need to try it on her.
The Science on CBD is positive for treatment of epilepsy- canine and human. The Science isn't in yet for treatment of anything else. Plenty of anecdotal evidence for this and that, but CBD in normal doses appears to be relatively harmless. Like everything else, any drug is good when not misused.