So you want a letter saying you need a support dog on that flight? Here’s why a therapist might balk

“This thing has gotten out of hand,” said Jeff Younggren, a psychologist and clinical professor at the University of New Mexico, who has conducted several studies on the subject of emotional support animals.

The number of passengers flying with emotional support animals on the nation’s airlines has surged. United Airlines, one of the biggest carriers, saw a 75% increase last year compared with 2016. The trend has been accompanied by more incidents of animals urinating, defecating, biting, barking and lunging on planes. A passenger was even mauled by a 50-pound dog on a Delta flight last year.


Despite the popularity of emotional support animals, experts say there’s little evidence they work

“We just don’t know whether they work or how much they work,” said Molly Crossman, a Yale University researcher who studies human and animal interactions.

There are few studies that examine emotional support animals, and the conclusions of these studies are mixed, she said. Also, the studies focus on dogs or horses, not other species. In her work, Crossman has found little evidence that animals can relieve anxiety or stress.

Still, those who work with animals designed to bring comfort to people struggling with mental health obstacles say people feel better after interacting with animals.