Because of extensive media coverage, it is now widely believed that pets enhance their owners' health, sense of psychological
well-being, and longevity. But while some researchers have reported that positive effects accrue from interacting with animals,
others have found that the health and happiness of pet owners is no better, and in some cases worse, than that of non–pet
owners. I discuss some reasons why studies of the effects of pets on people have produced conflicting results, and I argue that
the existence of a generalized "pet effect" on human mental and physical health is at present not a fact but an unsubstantiated
hypothesis.

1. Animal-assisted interventions 233
2. Animal-assisted therapies 448
3. Animal roles 319
4. human health 21
5. Pet ownership 193
6. Pets and companion animals 2468
7. psychological factors 79