An emotional support animal (ESA) is an animal that provides relief to individuals with "psychiatric disability through companionship." Emotional support animals are not required to be trained. Any animal that provides support, comfort, or aid, to an individual through companionship, unconditional positive regard, and affection may be regarded as an emotional support animal.

Animal-assisted therapy (AAT) is an alternative or complementary type of therapy that includes the use of animals in a treatment. The goal of this animal-assisted intervention is to improve a patient's social, emotional, or cognitive functioning. Studies have documented some positive effects of the therapy on subjective self-rating scales and on objective physiological measures such as blood pressure and hormone levels.