Authors: Barbara Natterson-Horowitz
This mute machine guards the entrance to a kingdom of euphoria. Locked inside are stacked drawers, each containing an array of highly addictive drugs. There are carousels of morphine vials. Pockets of Vicodin pills. Mini-bins stocked with Percoset and Oxycontin. Clear ampoules of fentanyl. All sit waiting but out of reach in the dark cabinet, unlit and unsparkling, like diamonds on black velvet trays deep in a Cartier safe.
The narcotics contained in this Pyxis MedStation 3500 drug-dispensing apparatus are essential for relaxing patients during medical procedures
and for relieving their pain afterward. But the box is there to deter a clever group of highly intelligent and crafty dope fiends: drug-seeking doctors and nurses. Hospitals have learned the hard way that easy on-the-job access can lead to addiction in their personnel. Brilliant colleagues, inventors of life-saving medical devices who rarely fail at anything, would find themselves red-faced, empty-handed, and referred into a career-salvaging “diversion program” if they tried to breach the machine to retrieve an unauthorized Vicodin. The lockbox—and the hospital has dozens of them—protects them from themselves.
That’s fine for a white-walled clinical suite where Vicodin tablets don’t grow on trees and fentanyl vials don’t dangle from vines. But the painkillers and sedatives in that machine are derived from natural opiates that do grow wild—in the
Papaver somniferum
poppy. Imagine the security system you’d need to protect several thousand square miles of poppy fields.
For opium-growing regions, this is a real issue.
In Tasmania, a leading producer of medical opium, users sometimes sneak into the fields.
Ignoring security cameras, they hop fences and gorge on poppy straw and sap. Dosed on the drug, they flail around in circles, damaging crops. Sometimes they pass out in the fields and have to be carried away in the morning. And there’s no way to prosecute these trespassing scofflaws, no rehab to send them to. Because these freeloading opium eaters are wallabies.
I have to admit that the thought of stoned wallabies made me smile.
Even the mug shot that accompanied the article in which I read about it was so “wrong”: a sweet-faced, gray-brown mini-kangaroo squints before an exotic backdrop of emerald-green poppy stalks. The tableau would be as lovable and cheeky as Peter Rabbit sneaking into Mr. McGregor’s garden … were it not for the animal’s zoned-out eyes and the fact that repeat offenders apparently have a serious drug problem.
Often, what’s endearing in animals is detestable in humans. So while we may chuckle at the intoxicated Tasmanian wallabies, we’d be justly horrified if they were Tasmanian children with a heroin habit. And if they were human adults, compulsively eating opium day after day, putting not just their own well-being but that of their families at risk, our horror might turn to disgust.
Indeed, this reaction points to one of the most frustrating, painful,
and puzzling aspects of drug addiction. Genetics, vulnerable brain chemistry, and environmental triggers play dominant roles in this illness. But ultimately, on the receiving end of the syringe, joint, or martini glass is a person making the choice, at least in the initial stages of substance use, to shoot up, smoke, or swallow.
To nonaddicts, that choice can be utterly perplexing. Users hemorrhage money, destroy careers, lose homes, and demolish relationships—all in pursuit of a high. Confoundingly, addicts who are parents sometimes make decisions that orphan their children. I’ve even seen patients stricken off the heart-transplant list—a literal death sentence for them—because they continued to use.
Despite advances in imaging and genetics that clearly characterize addiction as a brain illness, it remains uniquely bewildering. Why
is
it so hard for addicts to “just say no”? Is “can’t stop” really just an excuse for “won’t stop”? Whether we like it or not, confusion about how we should think about and classify addiction pervades our legal systems, schools, governments—and, frankly, even the field of medicine.
*
Addicts belong to a set of patients that society, even doctors, judges harshly. So well do addicts know this medical prejudice that they may hide their substance-use histories when they go to a doctor’s office or the ER, lest the level of care and compassion decline or disappear entirely. As one doctor I interviewed confided to me, “No one likes an addict.”
But nearly everyone likes a cute animal. And so it can be surprising to learn that animals, too—even if they must risk losing their children or, sometimes, their lives—plunder nature’s pharmacopoeia. With its vicious war between mind and body, addiction can seem distinctly human. But it turns out that our
Homo sapiens
bodies are not unique in the ways they react to intoxicating substances.
Understanding what drives animals to ingest drugs might help us separate what is inevitable from what is optional about this perplexing disease. The brain chemicals and structures that lead many millions of the world’s population to snort, shoot up, or chug are pervasive and powerful. As we’ll see, the urge to use has stayed in the gene pool for millions
of years and for a paradoxical reason. Although addiction can destroy, its existence may have promoted
survival
.
No one issued Flying While Intoxicated citations to the eighty cedar waxwing birds in Southern California who crashed into a reflective glass wall one February day. Drunk on fermented Brazilian pepper tree berries, they all died of spinal fractures and internal bleeding, some of them still clutching the mind-altering fruit in their beaks.
The Bohemian waxwings in Scandinavia that sometimes gorge on naturally alcoholic rowan berries and then fall into the snow and freeze to death have no irreverent nickname—unlike Russia’s
podsnezhniki
, or “snowdrops,” the human drunks who are discovered, dead, in thawing snowbanks every spring.
When a horse named Fat Boy nearly drowned in a neighbor’s swimming pool after getting sauced on ethanolized apples in a small English village, he made the evening news but didn’t have to apologize to the local fire brigade that pulled him out.
These animal encounters with intoxicants, however surprising and even amusing, were probably accidental. But others are not. Some animals show what seems to be more deliberate and chronic drug-seeking behaviors.
Bighorn sheep in the Canadian Rockies are reported to scale cliffs to get their fix of a psychoactive lichen and grind their teeth down to the gums scraping it off rocks.
In opium-producing regions of Asia, water buffalo (like Tasmania’s wallabies) are known to sample a daily dose of the bitter poppies and then show signs of withdrawal at the end of the flower-growing season.
The pen-tailed tree shrew that lives deep in the Segari Melintang rain forest in West Malaysia prefers the fermented nectar of the Bertram palm to all other food. The yeasty brew has an alcohol concentration comparable to that of beer (3.8 percent).
When cattle and horses that graze in the chaparral of the western United States lose their sense of direction, go weak in the legs, withdraw from other animals, or suddenly become violent, ranchers immediately suspect locoweed. Several varieties of this legume grow freely throughout the West; the numerous types can be identified by their blue, yellow, purple, or white blossoms that resemble small sweet peas. If the intoxicated livestock don’t die from walking off a cliff or blundering up to a predator, “locoed” animals can eventually starve or suffer severe, irreversible brain
damage. Despite these dire consequences, some animals actually prefer the plant over their regular foraging options—and, tellingly, one taste of it makes them more likely to try it again. In addition to misadventure and death, locoweed produces another nasty problem that annoys ranchers. Like the cool-kid druggie in homeroom, one locoweed-eating animal can influence others to start. Handlers must be assiduous about removing locoed animals from the herd so the weed-seeking behavior doesn’t spread. And locoweed affects wild animals, too. Elk, deer, and antelope have been seen staring dully and pacing nervously after a few nibbles.
A friendly cocker spaniel in Texas once sent her owners’ lives into a tailspin when she turned her attention to toad licking. Lady had been the perfect pet, until one day she got a taste of the hallucinogenic toxin on the skin of a cane toad. Soon she was obsessed with the back door, always begging to get out. She’d beeline to the pond in the backyard and sniff out the toads. Once she found them, she mouthed them so vigorously she sucked the pigment right out of their skin. According to her owners, after these amphibian benders Lady would be “disoriented and withdrawn, soporific and glassy-eyed.” Soon the neighbors’ dogs weren’t allowed to come over to play, for fear that they’d pick up Lady’s bad habit. Lady’s family dreaded the raised eyebrows when they hosted parties and PTA meetings and so started withdrawing from their social obligations because of the dog’s new inclination. As amusingly recounted in a story on National Public Radio, one night the dog’s human mistress found herself in the backyard at four in the morning, desperately searching for a toad to give to Lady—literally enabling the addiction so the dog would finally come inside and the family could get some sleep.
†
Giving alcohol to animals—or watching them imbibe on their own—has entertained humans for centuries.
In colonial New England, hogs that got tipsy after eating pomace (the pulpy by-product of cider production) may have provided the sounds that gave rise to a term popular in the day: “hog-whimpering drunk.”
Aristotle described Greek pigs becoming intoxicated when “
they were
filled with the husks of pressed grapes.” According to the author and alcohol historian Iain Gately, Aristotle also recorded a way to trap wild monkeys by enticing them with alcohol. The technique involved strategically laying out jugs of palm wine for the simians to sample and then simply plucking them up after they got drunk and passed out.
Apparently the trick worked just as well in the nineteenth century: Darwin described the same procedure in
The Descent of Man
.
‡
You can see modern-day drunken monkeys in a BBC video shot on the Caribbean island of St. Kitts. The Curious George look-alikes, with their bright, rounded faces, dart among bikini-clad hotel guests. Like teens at a wedding, they wait until no one’s looking, then run off with half-drunk daiquiris and mai tais. What comes next is enhanced by the video’s quick-cut editing but mirrors what happens to other animals, too, from squirrels drunk on fermented pumpkins to goats sauced on spoiled plums. The monkeys weave. They stagger. They list. They tip over. They try to stand up. They pass out.
§
Of course, comparing drug use in animals and in humans has limitations. The superpotent, rapidly addicting, Ph.D.-designed forms of opioids, marijuana, and cocaine peddled to and used by today’s human addicts differ significantly from naturally found plant sources of these psychoactive agents. The alcohol available to human consumers is much more refined and intense than what Mother Nature can make on her own. Furthermore, for scientists it’s frustrating that most examples of wild animal substance use and its effects are based on observation and anecdote. Indeed, the few papers that do examine wild animal models of intoxication bemoan this fact and call for more stringent field studies. But controlled conditions do occur more frequently in the lab, and animal drug use and abuse have been widely studied in that setting.
Rats, the most examined animal in substance abuse research, have revealed many crossover aspects of intoxication. Like us, in order to
start using a substance, they first must overcome an initial aversion.
They lose neuromuscular control when under the influence of certain drugs. They seek out and self-administer doses—sometimes to the point of death—of various drugs, from nicotine and caffeine to cocaine and heroin. Once addicted (researchers sometimes say “habituated”), they may forgo sex, food, and even water to get their drug of choice. Like us, they also use more when they’re stressed by pain, overcrowding, or subordinate social position. Some ignore their offspring. (Conversely, drug seeking can decrease in lactating female rats.) But rats, although they’ve become the most popular models for addiction in mammals, are not the only lab animals to be tempted by inebriating substances.
Bees “dance” more vigorously when they’re dosed with cocaine.
Immature zebrafish hang out on the side of the tank where they were once given morphine.
Methamphetamine juices snail memory and performance the way Ritalin might boost a sophomore’s PSAT scores.
Spiders on a range of drugs from marijuana to Benzedrine spin webs that are overly intricate or nonfunctional, depending on the drug.
Alcohol can make male fruit flies hypersexual and pursue more same-sex matings, perhaps because the ethanol interferes with their reproductive signaling mechanisms.
Even humble
Caenorhabditis elegans
, a tiny worm, moves more slowly when exposed to levels of alcohol similar to the ones that make mammals intoxicated. And the females lay fewer eggs when drunk.
Drug seeking. Raised tolerance. Attempts to get stronger and more frequent doses. Begging or jonesing for a drug. If human beings were the only creatures who showed these classic addiction behaviors, then we could say the disease is uniquely human. But clearly we aren’t alone. Across the animal kingdom—not just in mammals with highly developed brains—animals react to drugs in comparable, although of course not totally identical, ways.
That we can see parallel effects from intoxicants, whether the organism is a rodent, a reptile, a firefly, or a firefighter, strongly suggests two things. First, animal and human bodies and brains have evolved designated doorways for some of nature’s most potent drugs. Called receptors, these doorways are specialized channels on the outsides of cells that allow chemical molecules to enter.
Receptors for opiates, for example, have been found in some of Earth’s oldest types of fish as well as in humans,
and even in amphibians and insects.
Receptors for cannabinoids (the intoxicant found in marijuana) have been identified in birds, amphibians, fish, and mammals as well as mussels, leeches, and sea urchins. This introduces the biological likelihood that opiates and cannabinoids—plus many more psychoactive substances—play key roles in maintaining the health and safety of animals. Indeed, these drug-response systems may have evolved and endured because they actually
increase
an animal’s survival chances, or “fitness.” More on that in a moment.