Bottom line is, before you accepted the tenant, you're entitled to, and should not accept them without something in writing from a licensed Doctor or professional that designates the dog or "animal" as a prescriptive necessity.  

t out of Luck if they don't have a letter of prescription from a correctly licensed mental health profession with a right to practice in the state that the individual lives. 

Only a prescription by a doctor.

Potential tenant with felony prescription medication conviction, not violent, wasn't incarcerated, sounds like previous landlord said he pays on time.

Run an application all looks fine show up to sign lease docs and they have 5 pit bulls that are all "companion animals" 5 prescriptions one for each dog by name and description.  

Instead, they get a prescription and never go back to the prescribing doctor for treatment.Renewal every six months.

Los Angeles County, CIty of Signal HIllTenant with anxiety disorder presented with prescription from physician for daily medical cannabis inhalation.My first thought was, 'is that without filters by any chance?'

To @David Tubesing question about state specific laws, I can refer you to O.C.G.A. 48-4-48 that states in its entirety:(a) A title under a tax deed properly executed at a valid and legal sale prior to July 1, 1989, shall ripen by prescription after a period of seven years from the date of execution of that deed.

The apartment owners required tenants with disabilities to have a health care provider fill out a "prescription form" suggesting that he or she might be responsible for property damage or physical injury the assistance animal might cause.

The news stories about seniors not filling a prescription or splitting a pill to make them go further hit home for me because my dad did those things without telling anyone.