What causes, say, heroin addiction?
This is a really stupid question, right? It’s obvious; we all know it; heroin causes heroin addiction. Here’s how it works: if you use heroin for 20 days, by day 21, your body would physically crave the drug ferociously because there are chemical hooks in the drug.
That’s what addiction means. But there’s a catch.
Almost everything we think we know about addiction is wrong.
If you, for example, break your hip, you’ll be taken to a hospital and you’ll be given loads of diamorphine for weeks or even months. Diamorphine is heroin. It’s, in fact, much stronger heroin than any addict can get on the street because it’s not contaminated by all the stuff drug dealers dilute it with. There are people near you being given loads of deluxe heroin in hospitals right now.
So at least some of them should become addicts? But this has been closely studied; it doesn’t happen. Your grandmother wasn’t turned into a junkie by her hip replacement.
Why is that? Our current theory of addiction comes in part from a series of experiments that were carried out earlier in the 20th century.
The experiment is simple: you take a rat and put it in a cage with two water bottles. One is just water, the other is water laced with heroin or cocaine. Almost every time you run this experiment, the rat will become obsessed with the drugged water and keep coming back for more and more, until it kills itself.
But in the 1970s, Bruce Alexander, a professor of psychology, noticed something odd about this experiment: the rat is put in the cage all alone.
It has nothing to do but take the drugs. What would happen, he wondered, if we tried this differently? So he built Rat Park, which is basically heaven for rats; it’s a lush cage where the rats would have colored balls, tunnels to scamper down, plenty of friends to play with, and they could have loads of sex—everything a rat about town could want. And they would have the drugged water and the normal water bottles. But here’s the fascinating thing: in Rat Park, rats hardly ever use the drugged water; none of them ever use it compulsively; none of them ever overdose. But maybe this is a quirk of rats, right?
Well, helpfully, there was a human experiment along the same lines: the Vietnam War. 20% of American troops in Vietnam were using a lot of heroin. People back home were really panicked, because they thought there would be hundreds of thousands of junkies on the streets of the United States when the war was over. But a study followed the soldiers home and found something striking: they didn’t go to rehab; they didn’t even go into withdrawal; 95% of them just stopped after they got home. If you believe the old theory of addiction, that makes no sense. But if you believe Prof. Alexander’s theory, it makes perfect sense.