Imagine that you’re a wild rat. You spend your days searching for food, playfully poking at tree nuts (or candy wrappers) and socializing with your fellow rat brethren. It’s a complicated life, demanding intelligence and adaptation if you want to last long enough to pass on your genes to future generations.
Now imagine that you’re a caged rat inside a research lab. Your food is always provided to you. You have nothing to play with. You might have a rat roommate, but understanding complex pack politics is hardly necessary. How would this change your life? How would this change your mental health?
Rats and drug addiction
Lab rats are very good at getting addicted to drugs. In a famous PSA from the 1980s produced by the Partnership for a Drug-Free America, a rat appears to take cocaine repeatedly until it suffers from an overdose.
The narrator explains:
“Only one drug is so addictive that 9 out of 10 laboratory rats will use it … and use it … and use it until dead. It’s called cocaine and it can do the same thing to you.”
At a glance, this statement appears to agree with the scientific studies of the time: A study published in the Journal of the American Medical Association (JAMA) in 1985 found that 90 percent of rats — in other words, 9 out of 10 — would self-administer cocaine until death. Unfortunately, these scientists failed to recognize one glaring detail:
The rats in their study were bored.
Although many early scientific studies found that rats would self-administer cocaine to the point of harm, these studies neglected to give the rats anything else to do. The rats had no opportunities to play or socialize. They had no opportunities to solve puzzles or plan. The rats, desperate for something to do — anything to do — turned to cocaine.
A utopia for rats: Rat Park
The Canadian psychologist Bruce K. Alexander, Ph.D., recognized what many of his peers did not: The rats in early drug addiction studies weren’t representative of the average human — or the average rat. Wild rats typically live rich lives filled with scavenging and socializing. Humans, meanwhile, have jobs, families, friends and hobbies. Neither species was meant to live in a small cage with only food and cocaine as company.
And thus, the Rat Park was born.
Alexander, his colleagues and Simon Fraser University created a large colony designed to house 16 to 20 rats of each sex. These rats were given plenty of delicious food, a variety of toys and enough space for mating. When compared with a group of rats held in the traditional barren cages, these rats actually ignored the offered drugs. (The isolated rats, meanwhile, consumed a remarkable amount of morphine-laced water.) The results were published in the journal Psychopharmacology in 1978.
“I believe these results … show that the earlier animal self-administration studies provide no real empirical support for the belief in drug-induced addiction,” Alexander explained. “The intense appetite of isolated experimental animals for heroin and cocaine in self-injection experiments tells us nothing about the responsiveness of normal animals and people to these drugs. Normal people can ignore heroin and addiction even when it is plentiful in their environment … . Rats from ‘Rat Park’ seem to be no less discriminating.”
What does this mean for humans?
Drugs are addictive — there’s no question about that. It seems, however, that the drug itself is not enough to get the average person addicted. After all, most people who drink alcohol are not alcoholics, and most people who receive surgery don’t develop an addiction to pain killers. Why, then, do some people become addicts?
Drug addiction has a strong biological basis — in other words, some individuals have something inside them that makes them more likely to develop an addiction than other people. One scientific theory is that people who are predisposed to addiction have too few dopamine receptors. Dopamine is one of the neurotransmitters responsible for reward processing, or feeling good when something nice happens to you. A person might experience a rush of dopamine when seeing family members, making love or eating a particularly good meal. Individuals with too few dopamine receptors may be unable to feel pleasure like other people, requiring drugs to “fill the void.”
In other words, people who become addicted to drugs might be living in small cages with nothing to do, just like the laboratory rats. Nothing can bring them pleasure: not food, not hobbies, not friends. While the rest of us live in Rat Parks, addicts struggle to find something to do — anything to do — to make them happy. This is why treating addicts’ mental health — not just their addiction — is vital to the recovery process.