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The belief that animal therapy helps reduce stress is based on problematic research

Though animal-assisted therapy has been researched since at least the 1970s, the evidence to date does not offer a ringing support of its effectiveness.

Although animal-assisted therapy has been researched since at least the 1970s, the evidence to date does not offer a ringing support of the effectiveness of the practice.
REUTERS/Susana Vera

Therapy animals seem to be everywhere these days — in hospitals, nursing homes, college campuses, prisons, corporate offices, libraries and even at the sites of natural disasters.

The reason: a widespread belief that interacting with animals reduces psychological stress.

And it’s not only interactions with therapy dogs. Horses, cats, rabbits, goats, hedgehogs, pigs, parrots and even, yes, ducks, are among the long list of animals now used in both individual and group therapy programs.

Yet, although animal-assisted therapy has been researched since at least the 1970s, the evidence to date does not offer a ringing support of the effectiveness of the practice. That’s because studies on the subject have been problematic, with many methodological limitations.

“Research findings in support of [animal-assisted therapy] has not kept pace with the widespread prevalence in practice,” writes Molly Crossman, a Yale University doctoral student in psychology who recently published a long review of that research in the Journal of Clinical Psychology.

At best, the evidence suggests “a small-to-medium effect on distress, but does not clarify whether animals account for the treatment effects,” she writes.

A promising method

Animal-assisted therapy is certainly a promising method of reducing distress, particularly on a large scale. As Crossman points out, it’s very accessible — the animals are brought to locations where people already are. It’s also much more efficient that traditional one-on-one approaches to treatment. One program, for example, served 417 university students during six 90-minute sessions — or an average of 46 students per hour.

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Animal-assisted therapy also has the advantage of being perceived by the public as being effective at reducing distress. And it doesn’t carry the social stigma some people ascribe to traditional one-on-one therapy.

Yet despite these auspicious features, the research on the effectiveness of animal-assisted therapy has been problematic, says Crossman. For example, most of the studies have involved small numbers of people and have focused on the short-term effects on distress. They haven’t looked at whether this type of therapy has any long-term benefits.

Other problems with existing studies include generalizing across animals — the assumption that a patient’s positive interaction with one animal would be repeated in subsequent interactions with others.

And then there’s this inconvenient point: Many of the studies have found that  animal-assisted therapy has no effect on distress. “In a nutshell, some studies support the influence of [animal assisted therapy] on distress, but the overall state of the evidence is far from clear,” writes Crossman.

Concerns and controversies

A major concern regarding the existing research that has found a positive association between animal-assisted therapy and mood is this: Are the effects related to interaction with the animals or with the animals’ handlers?

Or, as Crossman asks: “Would any engaging and rewarding activity convey the same benefits?

That research needs to be done, she says, although such studies would be difficult to construct because of issues of ethics and safety. One possible solution would be to conduct the studies with the participants’ own companion animals rather than with ones brought by handlers.

Crossman also raises the highly controversial issue of emotional support animals — animals that are permitted to be in most public places because they have been deemed by a psychologist to be essential for that person’s wellbeing. (Emotional support animals should not be confused with working service dogs, which assist people who have physical or psychiatric disabilities.) 

As Crossman points out, there is considerable fraud regarding the designation of emotional support animals.

“Some healthcare providers will provide a prescription for an emotional support animal for a small fee,” she explains, “and fraudulent letters claiming that an animal is a specialized emotional support animal are readily available on the Internet.”

More rigorous research on animal-assisted therapy, Crossman points out, would help establish evidence-based standards for determining which patients would actually benefit from the effects of emotional support animals.

For more information: You’ll find an abstract of the review on the Journal of Clinical Psychology’s website, but the full article is behind a paywall.