While Emotional Support Animals or Comfort Animals are often used as part of a medical treatment plan as therapy animals, they are not considered service animals under the ADA. These support animals provide companionship, relieve loneliness, and sometimes help with depression, anxiety, and certain phobias, but do not have special training to perform tasks that assist people with disabilities. Even though some states have laws defining therapy animals, these animals are not limited to working with people with disabilities and therefore are not covered by federal laws protecting the use of service animals. Therapy animals provide people with therapeutic contact, usually in a clinical setting, to improve their physical, social, emotional, and/or cognitive functioning.
Information provided by ADA https://adata.org/publication/service-animals-booklet