What is an Emotional Support Animal (ESA)?

Emotional Support Animals offer support and comfort for psychiatric disabilities.
An ESA animal is NOT a service animal as defined by the ADA, therefore cannot go everywhere, however, this animal can go where any pets are permitted and in some no-pet areas, and can often fly free of charge, in airplane cabins.

Also known as Psychiatric Service dogs for a person identified as "disabled," either psychologically or emotionally - a person with a mental illness - the animal is tasked with the job of mitigating the disability or impairment.
Licensed Mental health Providers can write letters prescribing air travel or housing accommodations be made for persons with a psychiatric disability.

A store owner may not ask to see proof that this pet is a service animal - they may only ask, "Is this a service animal?" The same is true for federal and county buildings as well. The therapy dog does not need to be wearing a vest, sleeve or identification as such.

ESA's do not need special training. They are often "trained" by their human companion, to feel and intuit their owner's emotional condition, or anticipate their limiting behavior e.g., taking a shower and needing the dog nearby, securing the home premises at night before bed, responding to a doorbell or knock.

Psychotherapists can "prescribe" dogs, cats, pigs and other species to clients in need.
An ESA is often an alternative to medications or simply allows the client to more fully function in daily life, perhaps through great anxiety or panic attacks; a constant companion is something to touch and focus on, something to love, walk, feed, and brush.
An ESA is always a pleasant distraction with a calming influence.

Most importantly, an owner knows that his service pet "needs" his human, providing a sense of meaning and a great reason to carry on. 
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"Therapists are facilitators - not experts, not perfect human beings...just tour guides through the rough terrain."