I know somebody here who had their dog certified specially somehow - it's more than a therapy dog, maybe like a therapy companion animal. She has depression, I think, and possibly some other mental health issues (I'm not sure). She does have to pay the costs for the dog herself, although this enables her to take the dog with her most places. However, the certification isn't recognized the same way that a guide dog's certification is recognized. Not all businesses recognize it and they have the right to refuse entry to the dog, although I don't know how often that has happened. That's just our state though. It may be different in other states. I know it has given her a lot of comfort to take the dog with her as she does errands and such.

Take care,
ErinBear