I grew up in an apartment building that didn't allow pets, so I was slightly nervous when my husband, Jamie, and I adopted a dog nearly a decade ago. But it didn't take long before the aptly named Scrappy won me over, with her soft, floppy ears, oversize paws, clumsy playfulness and penchant for curling up on my feet. In fact, she quickly became a beloved member of the family, despite her unfortunate habit of running away and rolling around in foul-smelling messes.
Clearly, Scrappy brought a lot of happiness into our home, but Jamie has always insisted that having her around actually made him feel better: less anxious, for one thing, and much more relaxed.
A small body of research suggests that my husband was right. "We know that pets can have a positive health impact on people who feel positively about them," says Erika Friedmann, a professor at the University of Maryland School of Nursing and president of the International Society for Anthrozoology, whose members study human-animal interaction.
Friedmann's seminal 1980 research found that heart disease patients with pets had better one-year survival rates than similar patients without pets. More recently, studies have shown that pet ownership is associated with reduced stress, lower blood pressure, fewer doctor visits, less loneliness and increased social connectivity, and higher levels of physical activity.
Still, the findings haven't all been positive: Research published in a Scandinavian psychiatric journal followed 424 patients admitted to the hospital with acute coronary syndrome and found that pet owners - cat owners, in particular - were more likely to be readmitted or die within a year than patients who did not have cats. And the role of Fido or Fifi in childhood asthma and allergies remains an especially gray area, with some studies reporting that having a family pet early in life can trigger the development of these diseases, and others showing that the presence of an animal is a protective factor.
The confusion continued last fall, with the publication of a long-term study of 636 children in the Journal of Pediatrics. Researchers showed that kids with dog allergies were less likely to develop eczema by age 4 if they lived with a dog during their first year of life. The exact opposite was true for children who were allergic to cats and grew up with a cat in the house: They had a significantly increased risk of developing eczema later on than similar children who had no cat.
There's clearly a need for more - and better - scientific evidence about the link between pets and health.
"There is some good, solid research out there - a lot of tantalizing small studies - but there are also some methodological flaws with evidence for the positive effects of pets," says James Griffin, a scientist at the National Institute of Child Health and Human Development. One major limitation he cites is the difficulty of running "blind" studies, since people know when they are interacting with an animal. "That said, there are also a lot of methodological flaws in [studies] not showing that association or showing negative effects."