A cat that appears unwell by vomiting hairballs or refusing to eat may actually be healthy but just feeling out of sorts, according to a new study.

Researchers found that even healthy cats will appear sick when their routine is disrupted by a change in feeding schedule or caretaker. But restoring their routine and letting them feel somewhat in control may be all that’s needed to make them feel frisky again.

The study showed that healthy cats were just as likely to appear sick as cats with a chronic urinary tract illness called feline interstitial cystitis, when their normal environment was altered.

“A healthy cat — or any healthy mammal — can feel the stress of environmental disruption and exhibit sickness behaviors as a result,” says researcher Tony Buffington, professor of veterinary clinical sciences at Ohio State University, in a news release. “You get the environment right and they’ll recover.”

“When you have a cat that’s not eating, is not using the litter box or has stuff coming up out of its mouth, the quality of the environment is another cause that needs to be addressed,” says Buffington. “We are cautious about extrapolating these findings to the average home, but we will say that anyone who has a pet accepts the responsibility of understanding their pet’s needs and providing them.”

Effects of Disrupting Routine

In the study, researchers compared the number of sickness behaviors, such as vomiting, not eating, or refusing to use the litter box, among 12 healthy cats and 20 cats with feline interstitial cystitis, a chronic illness that causes recurring discomfort and pain in the bladder, following a change in their environment or routine.

During the weeks when the cats’ routine was unchanged, both the healthy cats and the cats with interstitial cystitis displayed few of these sickness behaviors, with an average of 0.4 events among the healthy cats and 0.7 among the cats with cystitis.

But during weeks when the cats’ routine was altered or normal caretaker was changed, the number of sickness behaviors more than tripled among both groups of cats. The healthy cats averaged 1.9 sickness behaviors and the cats with interstitial cystitis averaged 2.0.