July 16, 2013
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How much do we really know about addiction? The brutal truth is, not a lot. Sure, we’ve come a long way since the days when“treatment” involved the drunkard’s cloak or frying brains, but there are still some fairly hefty gaps in our knowledge. How is it that two people can use the same drug, but only one of them becomes addicted? Why do some people find quitting easier than others? And why does a cure for one person have no effect on the next?
It’s heartening to know, then, that in laboratories around the world, geneticists, psychologists, biologists and neuroscientists are carrying out all sorts of weird and wonderful experiments in the name of addiction research.
What’s my stake in this? Well, I’m no scientist, but I am deeply passionate about the subject. I’ve spent four years reading up on evolutionary psychology for my blog, Womanology, which is an attempt to fathom the mysteries of the dating world, and I’m a volunteer with Science London, a charity that organizes social events with a scientific twist. I’ve also battled my fair share of demons: In my 43 years on this earth, I’ve been hooked on gambling, pornography, tobacco, video games, alcohol and cocaine. (I’m pretty sure I’d have been addicted to sex, too, if I’d ever managed to track down a reliable supplier.)
So when I heard that Science London was putting on a talk called ” Addicted Fish: How useful are animal models in understanding the molecular and cellular mechanisms that underlie addiction?” I signed up like a shot.
Can fish really tell us anything about human behaviour? Whoever heard of a herring hooked on heroin?
The speaker was Dr. Matt Parker, a geneticist at Queen Mary University London (and until last month, it seems pertinent to mention, a 30-a-day man). He began, in front of a small but committed crowd in a room above a pub in central London, by addressing the question on everyone’s lips: Why fish?
Well, they’re not actually as different as you might think. You’ve no doubt heard the statistic that humans share 98% of their genes with chimpanzees. Well, it turns out that we also have around 85% of DNA in common with mice and rats–and a surprising 70% with zebrafish. The basic workings of most vertebrates, it turns out, are pretty similar.
The main sticking point for addiction research is that there’s only so much you can carry out on humans. You can perform tests (within limits) on people who are already addicted, but you can’t ethically make someone addicted and then see how their brain changes. (Some would argue that you can’t ethically do this to any living beings, but I’m not going to start that discussion here.) So for a long time, the experimental subject of choice has been that old standby, the rat.
It soon emerged that rats, like people, can develop pernicious habits. Scientists have bred coke-fiend rats, skaghead rats, chain-smoking rats and dipso rats, and they all exhibited symptoms similar to those seen in humans: anticipation, response to conditional cues (things associated with the stimulant, such as flashing lights), withdrawal symptoms and relapse.
They seemed to go through the exact same stages of dependency, too: irregular use, regular use, habitual use, cravings, a phase where they develop tolerance to the stimulant and experience withdrawal when denied it, and finally, the compulsive drug-seeking stage, when they will choose the drug ahead of more important things, such as food and sex.
In the tests, many of them at Cambridge University, a number of techniques were used to deliver the drug. Sometimes the rats would have to press a lever to obtain the stimulant; sometimes they would have to push their noses through a specific hole after a light flashed on.
Republished with permission from: AlterNet