Perhaps because we’re bombarded on all sides by animal cuteness, there’s something appealing about a book called “Animal Madness.” Enough with all the cuddling, you might think; it’s time for the real story, which Laurel Braitman, a historian of science with a Ph.D. from M.I.T., aims to tell. Where the BuzzFeed Animals page, for example, urges us to see animals as an undifferentiated mass of squee-worthy fluff, Braitman wants us to take animals seriously—to see them as individuals with life histories and psychologies as dramatic and intense as our own. Despite the winsome book design (there’s an adorably sad dog on the cover, and drawings of a glum raccoon and gorilla on the inside), there’s nothing remotely cute about this goal. “Animal Madness” is so upsetting, in fact, that I wanted to stop reading it about halfway through.

It’s obvious, of course, that animals of all sorts suffer from physical pain. It’s also obvious that many animals can be tense, unhappy, anxious, enraged, compulsive, impulsive, sad, depressed, and so on. Still, it’s tempting for many people, even sympathetic ones, to put those words in scare quotes—to see animal “depression” or “anxiety” as a less intense or consequential version of their human equivalents.

Braitman pushes back against that tendency. She has an absolute, not a comparative, sense of the animal soul. What matters isn’t how much an animal’s mental life is “worth,” compared to a person’s, but how wholly and powerfully it is illuminated by happiness or darkened by anguish. “Every animal with a mind has the capacity to lose hold of it from time to time,” she writes. An animal’s life can be changed utterly by mental illness, just like a person’s. A gorilla that sees her family killed, and that is kidnapped and brought to a zoo to live out her life on display, may have her whole existence reshaped by trauma, loneliness, and fear. Why argue about how intelligent she is? The point is that her life has been knocked off course and that she is suffering; she is no longer the animal she was.

Like people, Braitman writes, individual animals can be more or less prone to mental illness. But animals living in captivity—even pets—are more often pushed to the edge of sanity, frequently by factors wholly outside of their control. Constant visibility, social isolation, and a succession of strange environments make animals anxious, and the signs of that anxiety are, in turn, often highly visible: animals pluck their own feathers or pull out their fur, bite their tails or fins, regurgitate their food, pace ruts into the floors of their stalls or cells. Some animals, Braitman argues, are driven to despair—not some dumb, unthinking “animalistic” blankness but genuine spiritual emptiness. (Take a look at Arturo the polar bear, the “saddest bear in the world.”) Many zoo animals, she reports, are on anti-depressants, and the same goes for pets: the “animal-pharm” market—Prozac for pets, essentially—may be worth nine billion dollars a year by 2015. Braitman reports on the “blank stares” of captive gorillas and elephants; a marine biologist who she speaks with believes that “suicide in captive whales and dolphins is possible,” located “on a continuum with the other self-injurious things they do, like swimming in compulsive patterns or bashing their heads against the sides of their tanks.” “Animal Madness” opens with the story of Oliver, Braitman’s Bernese Mountain Dog. He was so overcome by separation anxiety, a common affliction among dogs, that he jumped out of her apartment’s fourth-floor window. (He survived, only to die later of another possibly stress-related ailment.)

Braitman knows that she will be charged with anthropomorphism, to which she has two rejoinders. First, she says, it is possible to “anthropomorphize well”—that is, to base your understanding of animal emotion on “shared generalities, not unfounded projections.” This, she points out, is how we relate to other people: we don’t know with certainty what someone is thinking or feeling, so we make our best guess based on things we have in common. Second, she points to history, arguing that our understanding of human mental illness has always been shaped by our understanding of animals and their minds. In the nineteenth century, it was often assumed that mentally ill people were regressing to a savage state; they were confined to zoo-like hospitals and made into objects of spectacle. Today’s psychiatry, too, is deeply shaped by animals. Pretty much every drug in the psychiatrist’s arsenal was refined through animal research, so when dogs and cats take Prozac or Valium we are mistaken if we think of them as animals taking people drugs. In many ways, the reverse is true. We share our basic emotional circuitry with many other animals, which is why scientists so often extrapolate from rats and monkeys to us. Early tranquilizers, such as Librium, proved their value through the “cat test”—pick up a drugged cat by the scruff of the neck and see what it does. (Cats given Librium “hung limply without struggling”; researchers were delighted to find that even cats “specially selected for their meanness” were “transformed into content, sociable, and playful felines.”) The fact that a drug relaxes both people and cats doesn’t mean that cat anxiety and human anxiety are equivalent, but it does suggest that they are analogous, and that an acknowledgment of that analogy is built in to the structure of psychiatry.

Some of the best material in “Animal Madness” explores just how far this kind of analogy can go. Braitman tells the story of Tip, a “mad” elephant who lived in the Central Park Zoo in the late nineteenth century. Tip arrived in New York in 1889 as a gift to the city from Adam Forepaugh, an American circus owner. Braitman thinks Forepaugh’s generosity was self-serving: Tip, having been abused for many years, may already have been mentally ill. The animal’s keeper, a man named William Snyder, became convinced that Tip wanted to kill him. In 1894, Tip knocked Snyder to the ground with his tusks, and moved to stomp on him (Snyder was pulled away just in time). Three years later, Tip tried again: “Tip swiped him with his tusks. The blow sent Snyder flying into the wall and the elephant quickly moved to gore the keeper while he lay prone on the floor. But Tip missed, hitting the wall of the pen so hard that the building shook.” Snyder’s “hatred of the elephant hardened into resolve to see him dead,” Braitman writes. A debate emerged: Should Tip be killed? While the Central Park commissioners weighed their options, people wrote in to the newspapers: