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“There are a few options for treating your depression,” I say to the patient. “But I think this medication may help.”

The patient starts laughing. “That’s pretty funny, Doctor.”

“I’m sorry?”

“My dog takes the same pill!”

The interface between pets and ­mental-health care has been a hot-button issue in recent years. The evidence that therapy animals can help treat people with psychiatric issues is patchy, yet emotional-support animals seem to be everywhere, perhaps most noticeably on planes. The Internet was in an uproar not long ago over reports that a traveler attempted to bring an emotional-support peacock onto a flight.

Meanwhile, veterinary providers and pet owners are paying increased attention to such problems as separation anxiety, compulsive behaviors, phobias and aggression in pets. As a result, many American pets are taking psychiatric medications.

“I think the increased use of psycho­active drugs comes from acceptance, even in the scientific community, that it’s okay to talk about fear, stress and anxiety in animals,” said Carlo Siracusa, a clinical assistant professor of behavior medicine at the University of Pennsylvania School of Veterinary Medicine.

On the basis of a 2017 national survey, the market research firm Packaged Facts concluded that 8 percent of dog owners and 6 percent of cat owners gave medications to their pets for anxiety, calming or mood purposes within the previous 12 months. Because about 60 million American households own dogs and 47 million households own cats, according to one estimate, these figures suggest that millions of animals in the United States are taking medications for behavioral issues.

Some versions of human medications have received approval by the Food and Drug Administration for specific mental-health uses in pets, including the antidepressant clomipramine (Clomicalm) for separation anxiety in dogs, the sedative dexmedetomidine (Sileo) for dogs with noise-aversion problems, and selegiline (Anipryl), a drug often used to treat Parkinson’s disease in humans, for canine cognitive dysfunction.

However, many if not most of the psychiatric medications given to pets are being used off-label — that is, for conditions other than the ones that the drugs were approved to treat. A survey of small-animal veterinarians published in 2016 found that 83 percent had prescribed the antidepressant fluoxetine (a.k.a. Prozac for humans) to cats and/or dogs, often for off-label uses such as treating inappropriate urination and aggression. Owners have written about giving common psychiatric drugs such as buspirone, trazodone and alprazolam (Xanax, for humans) to their pets. An article for the website the Daily Puppy publicizes risperidone, an antipsychotic used in humans for the treatment of schizophrenia and bipolar disorder, as an option for “improving your dog’s behavior.”

Whether pets really need these mood-altering drugs remains controversial. Nicholas Dodman, a professor emeritus at the Tufts University Cummings School of Veterinary Medicine and author of the book “Pets on the Couch,” has written that animals experience behavioral disorders similar to those of humans and that pets may need medications to alleviate their suffering. Treating these conditions, Dodman says, might also prevent some pets with behavioral issues from being sent to shelters or from being euthanized.

Siracusa said that the use of psychiatric drugs in veterinary medicine represents a shift away from poorly regulated “punishment-based behavior modification” such as shock collars for dogs that bark too much. “If you have to use a psychoactive drug, you have to talk to a vet, right?” he said. “If you have to use the shock collar, you just go on Amazon and buy it yourself,” he said, adding, “The psychoactive drug is probably more benign of all the possible terrible things that [people] could do to animals when [they] don’t like their behavior.”

Yet it’s not entirely clear how often these medications are used to truly care for pets, as opposed to being used for the convenience of pet owners. In a 2015 column in The Washington Post, veterinarian Michael W. Fox wrote about his concerns regarding “the overreliance on psychopharmaceuticals to help animals adapt to situations in which they do not belong — such as a dog being left at home in a crate all day.” While drugs may be helpful in some cases, he wrote, “the trend of applying mind-altering drugs to help animals cope in stimulation-lacking and socially deprived domestic environments is an ethical concern that all responsible parties need to address.”

There is at least some published evidence to support treating pets with psychiatric drugs. In particular, randomized, ­placebo-controlled trials suggest that antidepressants may help dogs suffering from separation anxiety or compulsive behaviors such as tail chasing. But several of these studies received some funding from the pharmaceutical companies marketing these drugs to veterinarians and pet owners. These studies also frequently showed mixed results or included behavioral therapies as part of the treatments for animals.

Critics of giving pets psychiatric medications argue that owners should rely more on behavioral approaches, such as spending more time with pets, taking them outdoors and using training programs. Research supports the notion that environmental factors probably play a role in the development of behavioral issues in pets. Perhaps unsurprisingly, studies suggest that dogs who are walked only a few times each week or whose owners spend less time at home may be at greater risk for behavioral problems, such as excessive barking and destructiveness.

Still, there are situations that seem to warrant treating pets with psychiatric medications. For instance, veterinary staff often suffer injuries such as lacerations and bites from agitated animals. Under these circumstances, veterinarians may turn to such medications as acepromazine — a medication similar to chlorpromazine, the first antipsychotic widely used in humans — to help sedate aggressive pets.

Giving these kinds of drugs to pets isn’t risk-free. Just as with humans, psychiatric medications for pets can carry plenty of side effects, including gastrointestinal upset, weight changes and irregular heartbeats.

The overlapping use of psychiatric medications among humans and animals also raises the specter of owners sharing drugs with their pets. Veterinarians have voiced concerns about owners using pets to obtain access to restricted drugs, including anti-pain opioids and anti-anxiety benzodiazepines. (Some states now require veterinarians to file reports to authorities when prescribing controlled substances for pets.)

Veterinary organizations are establishing frameworks to guide the use of psychiatric drugs in pets. In 2015, the American Animal Hospital Association published practice guidelines for the behavioral management of cats and dogs, including recommendations regarding when medications may be helpful to these animals. Several academic institutions now offer specialized training in animal behavior for veterinarians, including board certification in the specialty by the American College of Veterinary Behaviorists.

Pets undoubtedly have mental-health needs that deserve our attention. But as a doctor specializing in mental-health care for people, I’ve learned that prescribing psychiatric medications often comes with a great deal of uncertainty.

I can only imagine how hard it must be when the patients cannot speak their minds.

health-science@washpost.com

Morris is a resident physician in psychiatry at the Stanford University School of Medicine.