Drug addiction: The complex truth

We’re told studies have proven that drugs like heroin and cocaine instantly hook a user. But it isn’t that simple – little-known experiments over 30 years ago tell a very different tale.

Drugs are scary. The words “heroin” and “cocaine” make people flinch. It’s not just the associations with crime and harmful health effects, but also the notion that these substances can undermine the identities of those who take them. One try, we’re told, is enough to get us hooked. This, it would seem, is confirmed by animal experiments.

Many studies have shown rats and monkeys will neglect food and drink in favour of pressing levers to obtain morphine (the lab form of heroin). With the right experimental set up, some rats will self-administer drugs until they die. At first glance it looks like a simple case of the laboratory animals losing control of their actions to the drugs they need. It’s easy to see in this a frightening scientific fable about the power of these drugs to rob us of our free will.

But there is more to the real scientific story, even if it isn’t widely talked about. The results of a set of little-known experiments carried out more than 30 years ago paint a very different picture, and illustrate how easy it is for neuroscience to be twisted to pander to popular anxieties. The vital missing evidence is a series of studies carried out in the late 1970s in what has become known as “Rat Park”. Canadian psychologist Bruce Alexander, at the Simon Fraser University in British Columbia, Canada, suspected that the preference of rats to morphine over water in previous experiments might be affected by their housing conditions.

To test his hypothesis he built an enclosure measuring 95 square feet (8.8 square metres) for a colony of rats of both sexes. Not only was this around 200 times the area of standard rodent cages, but Rat Park had decorated walls, running wheels and nesting areas. Inhabitants had access to a plentiful supply of food, perhaps most importantly the rats lived in it together.

Rats are smart, social creatures. Living in a small cage on their own is a form of sensory deprivation. Rat Park was what neuroscientists would call an enriched environment, or – if you prefer to look at it this way – a non-deprived one. In Alexander’s tests, rats reared in cages drank as much as 20 times more morphine than those brought up in Rat Park. 

Inhabitants of Rat Park could be induced to drink more of the morphine if it was mixed with sugar, but a control experiment suggested that this was because they liked the sugar, rather than because the sugar allowed them to ignore the bitter taste of the morphine long enough to get addicted. When naloxone, which blocks the effects of morphine, was added to the morphine-sugar mix, the rats’ consumption didn’t drop. In fact, their consumption increased, suggesting they were actively trying to avoid the effects of morphine, but would put up with it in order to get sugar.

Woefully incomplete’

The results are catastrophic for the simplistic idea that one use of a drug inevitably hooks the user by rewiring their brain. When Alexander’s rats were given something better to do than sit in a bare cage they turned their noses up at morphine because they preferred playing with their friends and exploring their surroundings to getting high.

Further support for his emphasis on living conditions came from another set of tests his team carried out in which rats brought up in ordinary cages were forced to consume morphine for 57 days in a row. If anything should create the conditions for chemical rewiring of their brains, this should be it. But once these rats were moved to Rat Park they chose water over morphine when given the choice, although they did exhibit some minor withdrawal symptoms.

You can read more about Rat Park in the original scientific report. A good summary is in this comic by Stuart McMillen. The results aren’t widely cited in the scientific literature, and the studies were discontinued after a few years because they couldn’t attract funding. There have been criticisms of the study’s design and the few attempts that have been made to replicate the results have been mixed.

Nonetheless the research does demonstrate that the standard “exposure model” of addiction is woefully incomplete. It takes far more than the simple experience of a drug – even drugs as powerful as cocaine and heroin – to make you an addict. The alternatives you have to drug use, which will be influenced by your social and physical environment, play important roles as well as the brute pleasure delivered via the chemical assault on your reward circuits.

For a psychologist like me it suggests that even addictions can be thought of using the same theories we use to think about other choices, there isn’t a special exception for drug-related choices. Rat Park also suggests that when stories about the effects of drugs on the brain are promoted to the neglect of the discussion of the personal and social contexts of addiction, science is servicing our collective anxieties rather than informing us.

This is my BBC Future article from tuesday. The original is here. The Foddy article I link to in the last paragraph is great, read that. As is Stuart’s comic.

34 Comments

  1. Posted September 13, 2013 at 9:57 am | Permalink

    To my mind this mechanism explains also the high incidence of mental disorders in drug users. People self medicate due to lack of proper support. It’s irritating to see many studies making the inverse conclusion that drugs cause mental disorders. Also the dutch free heroin on prescription showed that addicts can function completely normally in society once the time/effort needed to obtain the product has been eliminated. Also the inverse cannabis/psychosis studies are annoying since they prohibit politicians making the right policies.
    A worrying example is France where deadly violence due to the illegal cannabis trade has reached 1930′s gangster proportions with the only difference that the tommygun has been replaced with the AK47. The asinine response of the french government is to increase the war on cannabis whilst its blindingly obvious to common sense that legalizing it would take away the majority of reasons for the voilence.

  2. eltelrobinson
    Posted September 13, 2013 at 10:34 am | Permalink

    Any open access versions of original paper or foddy article please?

  3. rmgw
    Posted September 13, 2013 at 11:27 am | Permalink

    Carl Hart says more or less the same in his book.”High Price”. Like the previous commentator, I am horrified by the destructive effect of the asinine “war on drugs”, counter-scientific and inhuman.

    Anything less ethical than drawing nonhumans into this ridiculous, cruel and counter productive business can hardly be imagined, unless it’s to show that callousness is at the root of this human behaviour as well as that displayed to the poor which drives them into drugs in the first place.

  4. wtpayne
    Posted September 13, 2013 at 11:59 am | Permalink

    It makes intuitive sense that an environment with limited freedom, limited exercise, limited social interaction and limited “play” would promote both stress and the formation of patterns of addiction. Could this be another factor linking poverty and substance abuse?

  5. Posted September 13, 2013 at 12:47 pm | Permalink

    “The asinine response of the french government is to increase the war on cannabis whilst its blindingly obvious to common sense that legalizing it would take away the majority of reasons for the voilence.”

    Would legalizing cannabis take away human GREED?

    Many say Prohibition was stupid. Yet, look at America now. There are so many alcoholic and drug rehab and social services and dysfunctional families from LEGALIZING ALCOHOL…Did that really remove VIOLENCE? How many alcoholic fathers beat their children and wives? How about DUI and drunk drivers?

    If legalizing alcohol was supposed to remove violence someone forgot to tell New Orleans as it has a murder rate 10 times the national average, highest poverty rates and illiteracy rates in America, yet has the most bars per capita in America.

    Oh, and isn’t America 16 TRILLION in debt from social services that are supporting the effects of ALCOHOL via dysfunction families, via Section 8 housing, EBT, food stamps, rehabs, health services, mental health services, schools with kids from dysfunctional families where parents and teachers blame each other, etc…

    And what about Europe? If legalization was working there, where is the MONEY? They have so many social programs the EURO is about to breakup and how many bailouts????

    • mattoid
      Posted September 13, 2013 at 2:35 pm | Permalink

      To suggest that the Euro problem is due to legal alchohol is simply dishonest. Legalised alchohol? It was never illegal! Please.
      You blame the alchohol. Anyone with an ounce of sense can see that the problem begins with the poverty, as clearly shown in the studies quoted above.
      I think if you want to look for where the US is in debt from, look to all those stupid wars you insist on starting, and the millions in jail over cannabis. There’s your national addictions.

      You simply have an agenda and will bend any old factoid to try and support it. Must try harder.

    • Posted September 13, 2013 at 4:17 pm | Permalink

      The Netherlands it’s working fine, except that they have to work around EU legislation which makes it rather messy legalwise. Which is the reason they can’t levy tax, else they’d done it already. As it stand snow the larger cities are starting giving cannabis culture permits to professional agriculturists. As for addiction etc. the level of addiction,related crime, health problems is still directly linked to the level of criminalization, where USA scores worst and the Netherlands scores best.
      As for being in debt, i fail to see how that’s drug related and/or relevant

    • Mike
      Posted September 13, 2013 at 4:22 pm | Permalink

      Your comment raises just a single question: Why do people with minimal knowledge insist on joining the public debate of any given topic? Or, perhaps, why do some people think misrepresentation is a strong argument?

      The rest is pretty laughable.

  6. Kate
    Posted September 13, 2013 at 3:15 pm | Permalink

    Europe is a continent. I know your education system is through the floor but nonetheless…

  7. Posted September 13, 2013 at 4:30 pm | Permalink

    > “The Netherlands it’s working fine, except that they have to work around EU legislation which makes it rather messy legalwise.”

    If the Netherlands is working fine, why do Russian men, who have a high number of alcoholic, e.g. vodka, have a very very low life expectancy? And in fact, Russia’s population is decreasing so bad due to alcohol, they have to PAY women to have babies!!!

    And how many men in Afghanistan are under the influence of drugs like opium? And how are they doing?

    Or what about those Latin American countries that are biggest exporters of drugs? If they are doing so well with legalzing drugs, why are they so poor that their workers can’t find jobs in Latin America? Why are they fleeing those drug countries if it is so great to legalize drugs?

    • Posted September 13, 2013 at 4:38 pm | Permalink

      Because people try to escape the nasty reality of a crappy world. Very simple. That’s why. Has nothing to do with legalization. Since 40 yrs the Netherlands have semilegal cannabis & hard drugs. The level of addicts remains the same/lower.

      Exceptions taken into account people do drugs because the world they live in is to crap to take on sober.

    • Mike
      Posted September 13, 2013 at 4:41 pm | Permalink

      What does the lifespan of Russian men have to do with The Netherlands?

      What does alcohol addiction in Russia have to do with The Netherlands’ Marijuana usage?

      How have you concluded that Russia’s population decline is due solely to alcohol? Surely alcohol is just a single reason in a sea of many.

      Afghanistan has always been a major supplier of opium to other countries. There are obviously pros and cons to allowing a percentage of your farming population to grow poppies while drug use is forbidden. Do you have anything specific to say about it?

      What Latin American countries have legalized export of narcotics? How have you concluded all of their societal woes are the result of illicit drugs?

    • jrkrideau
      Posted September 22, 2013 at 11:45 pm | Permalink

      “Europe is a continent. I know your education system is through the floor but nonetheless…”

      And I thought Kate was being unkind.

      • Posted September 23, 2013 at 9:23 am | Permalink

        if i’d had to correct each time someone confused European Union and Europe i’d do nothing else

  8. Bill Cornelius
    Posted September 13, 2013 at 6:48 pm | Permalink

    the missing quality is intent. drugs are taken to to see god, or simply break the law, or get wasted and screw (escape). those motivations influence the resulting actions, and the reaction of an observer. what would happen to rats started on one regiem and switched to the other after an interval?

  9. John R. Vokey
    Posted September 13, 2013 at 8:37 pm | Permalink

    Of course, the standard approach to addiction also omits the large and necessary role of pavlovian conditioning:

    @article{siegel1998learning,
    title={Learning and homeostasis: drug addiction and the McCollough effect.},
    author={Siegel, Shepard and Allan, Lorraine G},
    journal={Psychological Bulletin},
    volume={124},
    number={2},
    pages={230},
    year={1998},
    publisher={American Psychological Association}

  10. Posted September 13, 2013 at 9:18 pm | Permalink

    Interesting as most animal experiment labs would tell you the severe and desolate cage environment is to ensure uniformity in methods and results. Of course they’re RATS and why we think ourselves so important we should torture them to solve moronic human problems is beyond me. If rats (and hello, primates) are so “social and similar to humans” why is this legal? Can anyone say why a human life is more valuable than a rat’s? I’m serious.

    • simone
      Posted September 14, 2013 at 1:21 am | Permalink

      I don’t think it is a ‘humans are more important’ issue in regards to animal experimentation. It is just that there are currently not many other options to test hypotheses — can’t do human studies till you try it out on non-human animals first. We have to give our own species more consideration.

      Plus, if we stopped all animal experimentation, how would grad-students prove their thesis? There is a huge market out there that would crash (it is bigger than you’d realize); jobs would be lost, equipment manufactures & labs shut down, …etc …

      Similar to why we still put up with power plants burning coal. We need electricity. If that is how they run, we can’t just turn the power off and wait for them to implement something new, untested, and won’t produce as much energy as the current system does. It has to be done in stages. There is a lot less experimentation done on animals now then there used to be — due to improvements in software simulation technology. However, it is still in the development stages.

      • Posted September 14, 2013 at 8:46 am | Permalink

        Thanks for the reply Simone, although I was referring to ethics. In any case, it’s interesting how an environment can affect humans. We’ll learn more about this as climate change progresses or when we’re all watching the Mars victims on reality T.V.

  11. Posted September 13, 2013 at 10:34 pm | Permalink

    Having been around drug and alcohol treatment centers for quite a while, I feel very confident in saying that addiction is directly related to attachment disorder. Sure there is likely a physiological or hereditary tendency but the perfect storm happens when someone with attachment issues and the appropriate genetic markers is introduced to the drug. It’s much the same as a platoon of soldiers in combat, all experiencing the same hell, when only one or two will experience PTSD.

  12. Posted September 13, 2013 at 10:41 pm | Permalink

    I am shocked at both the treatment of the mentally ill and drug addicts in our prison system. I believe both of these are diseases that should be delt with outside of prison. Here is an interesting video http://www.youtube.com/watch?v=tYvKfIDPoXY , thanks for the article.

  13. Posted September 13, 2013 at 10:49 pm | Permalink

    Read Gabor Mate talking about “attachment disorder” and addiction. I think when someone with attachment issues and a genetic propensity for addiction, you have the perfect storm.

    • carrie
      Posted September 14, 2013 at 7:13 am | Permalink

      Do you have a link to the mate article you’re referring to? Thanks.

  14. rmgw
    Posted September 14, 2013 at 9:07 am | Permalink

    It’s the terrible price that communities in places like Colombia pay for the wretched war on drugs which seems peculiarly unfair to me.

  15. Posted September 15, 2013 at 11:18 am | Permalink

    Folks, there is more than one issue here. The original point of the article, as I see it, was a critique of the way neuroscience findings are seized upon, gullibly, eclipsing all other accounts. The issue of drugs, the moral panic they have evoked, and the economic and political costs, was just an example. (And gross lapses of netiquette are commonest when such passions are aroused.) But I’d like to get back to the earlier, more science-y point. There are other studies of the beneficial effects of environment on promoting resilience and well-being, most of which are overlooked by a science establishment pre-occupied with medical solutions (since they are more readily marketable?). My favourite is a study [Döbrössy & Dunnett, 2008] that showed that “enriched housing “(sic) combats the onset and severity of Huntingdon’s Disease – one the few illnesses for which a single gene genetic causal factor is well established. There are similar studies of recovery from head injury, and a host of similar conditions. The point here is that for the general public, and politicians, under-valuing of research on built environment effects is systemic – but is now becoming recognised within the research couunity.

  16. Posted September 16, 2013 at 10:19 am | Permalink

    Twelve years ago, Portugal eliminated criminal penalties for drug users. Since then, those caught with small amounts of marijuana, cocaine or heroin go unindicted and possession is a misdemeanor on par with illegal parking. Experts are pleased with the results.

    http://www.spiegel.de/international/europe/evaluating-drug-decriminalization-in-portugal-12-years-later-a-891060.html

    • Bill Cornelius
      Posted September 17, 2013 at 8:21 pm | Permalink

      Being instantly hooked by heroin & Cocaine is false but the concept comes from observations of dissolution and personal fear of being that way (loss of status, giving up, etc). Politically, that fear is a hot button. It can be used to justify wars or anything. A nation of users would need an embassy in DC. There’s obviously money available but it’s all going into development of the problem instead of it’s resolution. A plan would help.

  17. Posted September 17, 2013 at 8:33 pm | Permalink

    >But there is more to the real scientific story, even if it isn’t widely talked about.

    Fortunately, David Sheff has restarted the conversation on the complexity of addiction with his 2013 bestselling book Clean: Overcoming Addiction and Ending America’s Greatest Tragedy (as of this writing, #7150 on Amazon). He writes, “Given the current state of science’s understanding of addiction, there’s no conclusive answer as to why one person’s drug use escalates and another’s doesn’t. Everyone’s different, and everyone reacts differently to different drugs, different amounts and combinations of them, and different ways drugs are administered, because of each person’s unique biology, psychology, and environment. But some factors that influence the likelihood of addiction are known” (p.81). This corroborates tomstafford’s point, “It takes far more than the simple experience of a drug – even drugs as powerful as cocaine and heroin – to make you an addict.” Sheff cites factors such as age of first use, genetics, and pre-existing psychiatric illnesses. For those interested, Chapter 5 explores current thought on the origins of addictions more thoroughly.

  18. Posted September 18, 2013 at 3:19 pm | Permalink

    If environment is a factor, has no one thought of outdoor fitness as a treatment? I don’t mean to take the “environment” findings literally. But a matter of enrichment combined with the “runner’s high” seems like a logical choice.

    Of course getting drug addicts to hit the trails is a whole other matter. But I think at least some would be willing to try.

    • Posted September 18, 2013 at 3:26 pm | Permalink

      20% of first aid admissions are sports related. Less then 20% are drugs related. Seems a rather ineffectual solution cost wise

  19. gyges
    Posted September 30, 2013 at 9:18 pm | Permalink

    In the 1970s an academic, a chemist at one of the London Universities, walked into the common room and declared to all and sundry that he thought that drug addiction was a myth. What’s more, he said, he was going to prove it. He bought some heroin from one of the chemical suppliers, injected himself with the appropriate dose for a month and then at the end of this month … stopped. He simply packed it in with no ill effects.

    No doubt a great number of your readership will know (or can guess) who the chap was.


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