Psychiatric Service Dogs (PSDs) are service dogs individually trained to perform tasks which mitigate the psychiatric disabilities of their disabled partners.
There has been some confusion and some heated debate about psychiatric service dogs (PSDs). First let's clarify the difference between a therapy dog and a psychiatric service dog. A therapy dog is an individual's pet which has been trained, tested, registered and insured to work in hospital, nursing home, school, or other institutional setting. The therapy dog and his partner visit to cheer patients, to educate the community, to counter grief and stress, and generally be good canine ambassadors within the community. Most therapy dog partners are volunteers, but some states recognize professional therapy dogs partnered with therapists and other mental health professionals. Therapy dogs are not service dogs.
Under U.S. law, persons with therapy dogs are NOT granted the right to enter businesses that do not permit pets with their therapy dogs, unless they get permission from the business first. This includes the hospitals and nursing homes they visit to work with the patients and residents there. They do not get to fly in the cabins of aircraft because they are therapy dogs, nor do they get to live in "no pets" housing because they are therapy dogs.
Dogs used for emotional support, that are not task-trained, are called emotional support animals. They are not PSDs or any other kind of service dog, though they are grouped with service dogs in housing laws and laws governing commercial aircraft.