The Drug Addictions Of Mice And Men

In my post, I mentioned the very real possibility that as people’s personal biases make their way into research, the quality of that research might begin to decline. More generally, I believe that such an issue arises because of what the interpretation of some results says about the association value of particular groups or individuals. After all, if I believed (correctly) that people like you tend to be more or less [cooperative/aggressive/intelligent/promiscuous/etc] than others, it would be a fairly rational strategy for me to adjust my behavior around you accordingly if I had no information about you other than that piece of information. Anyone who has feared being mugged by a group of adolescent males at night and not feared being mugged by a group of children at a playground during the day understand this point intuitively. As a result, some people might – intentionally or not – game their research towards obtaining certain patterns of results that reflect positively or negative on other groups or, as in today’s case, highlight some research other people as being particularly important because it encourages us to treat others a certain way. So let’s talk about giving drugs to mice and men.

Way to set a positive example for the kids, Mickey

The article which inspired this post was written by Johann Hari, and the message of it is that the likely cause of drug addiction (and, perhaps, other addictions as well) is that people fail to bond with other humans, bonding instead with drugs. This is, according to Johann, quite a distinct explanation than the one that many people favor: that some chemical hooks in the drugs alter our brains in such a way as to make us crave them. To make this point, Johann highlights the importance of the Rat Park experiment, in which rats placed in enriched environments failed to develop addictions to opiates (which were placed in one of their water bottles), whereas rats placed in isolated and stressful environments tended to develop the addictions to the drugs readily. However, when the isolated rats were moved into the enriched environments, their preference for the drug all but vanished.

The conclusion drawn from this research is that the rats – and, by extension, humans – only really use drugs when their environments are harsh. One quote that really drew my attention was the following passage:

“A heroin addict has bonded with heroin because she couldn’t bond as fully with anything else. So the opposite of addiction is not sobriety. It is human connection.”

I find this interpretation to be incomplete and stated far too boldly. One rather troublesome thorn for this explanation rears its head only a few passages later, when Johann is discussing how the nicotine patch does not help most smokers successfully quit; about 18% is the quoted percentage of those who quit through the patch, though that percentage is not properly sourced. From the gallup poll data I dug up, we can see that approximately 5% of those who have quit smoking attribute their success to the patch. That seems like a low number, and one that doesn’t quite fit with the chemical hook hypothesis. Another number sticks out, though: the number of people who attribute their success in quitting to support from friends and family. If Johann’s hypothesis is correct and people are like isolated rats in a cage when addicted, we might expect the number who quit successfully through social support to be quite high. If addiction is the opposite of human connection, as human connections increase, addiction should drop. Unfortunately for his hypothesis, only 6% of ex-smokers attribute their success to those social factors. By contrast, about 50% of the ex-smokers cited just deciding it was time and quitting cold turkey as their preferred method. Now it’s possible that they’re incorrect – that has been known to happen when you ask people to introspect – but I don’t see any reason to assume they are incorrect by default. In fact, many of the habitual smokers I’ve known did not seem like people lacking social connections to begin with; smoking was quite the social activity, and many people started smoking because their friends did. That is, they might developed their addiction through building social connections; not through lacking them.

Indeed, his hypothesis is all the stranger when considering the failure of people using the patch to successfully kick their habit. If, as Johann suggested, people are bonding with chemicals instead of people, it would sound as if giving them the chemicals in question should correspondingly cut down on their urge to smoke. That it doesn’t seem to do so very much is rather peculiar, suggesting something is wrong with the patches or the hypothesis. So what’s going on here? Is addiction to cigarettes different than addiction to opiates, explaining the disconnect from the Rat Park results to the cigarette data? That might be one possibility, though there is another: it is possible that, like quite a bit of psychology research, the Rat Park results don’t replicate so nicely.

“Reply still hazy; try controlling for gender and look again”

Petrie (1996) reports on an attempted replications of the rat park style of research that did not quite pan out as one might hope. In the first experiment, two groups of 10 rats were tested. The first group was raised in isolated conditions from weaning (21 days old), in relatively small cages without much to do; the second group was raised collectively in a much larger and more comfortable enclosure. These enclosures both contained food and water dispensers, freely available at all hours. In order to measure how much water was being consumed, each rat was marked for identification, and each trip to the drinking spout triggered a recording device. The weight of the water consumed was automatically recorded after each trip to the spout as well.  The testing began when the rats were 113 days old, lasting about 30 days, at which points the rats were all killed (which I assume is standard operating procedure for this kind of thing).

During that testing period, animals had access to two kinds of water: tap water and the experimental batch. The experimental batch was flavored with a sweetener initially, whereas on later trials various concentrations of morphine were also added to the bottle (in decreasing amounts from 1 mg to 0.125 mg, cutting by half each time). Across every concentration of morphine, the socially-reared rats drank slightly more than their isolated counterparts: at 1 mg of morphine, the average number of grams of experimental fluid consumed daily by the social group was 3.6 to the isolated rats 0; at 0.5 mg of morphine, these numbers were 1.3 and 0.5, respectively; at 0.25 mg morphine, 18.3 and 15.7; at 0.125 mg, 42.8 and 30.2. In a second follow up study without the automated measuring tools, this pattern was reversed, with the isolated rats tending to drink slightly more of the morphine water during 3 of the 4 testing phases (those numbers, in concentrations of morphine as before, with respect to social/isolated rats were: 4.3/0.3; 3.0/9.4; 10.9/17.4; and 33.1/44.4). So the results seems somewhat inconsistent, and the differences aren’t all that large. The differences in these studies did not even come close to the original reports of previous research claiming that the isolated rats drank up to 7-times as much.

To explain at least some of this difference in results, Petrie (1996) notes that some genetic differences might exist between the rat strains utilized between the two. If that was the case, then the implication of that is – like always – that the story is not nearly as simple as “bad environments cause” people to use drugs; there are other factors to think about, which I’ll get to in a moment. Suffice it to say right now that, in humans, it seems clear that recreational drug use is inherently more pleasant for certain people. Petrie (1996) also notes that the rats tended to consume the same absolute amount of morphine during each phrase, regardless of its concentration in the water. The rats seemed to much prefer the sweetened to the tap water by a huge margin when it was just sucrose, but drank less sweetened water when the morphine (or another bitter additive) was added, so it’s likely that the rats did not quite enjoy the taste of the morphine all that much. The author concludes that it’s probable the rats enjoyed the taste of the sugar more than they enjoyed the morphine’s effects.

An affinity many humans seem to share as well

The Petrie (1996) paper and the cigarette data, then, ought to cause us some degree of pause when assessing the truth value of Johann’s claims concerning the roots of addiction. Also worrying is the moralization that Johann engages in when he writes the following:

“The rise of addiction is a symptom of a deeper sickness in the way we live — constantly directing our gaze towards the next shiny object we should buy, rather than the human beings all around us.”

This hypothesis of his seems to strike me as the strangest of all. He is suggesting, if I am understanding him correctly, that people (a) find human connections more pleasurable than material items or drugs, like rats, but (b) voluntarily forgo human connections in the pursuit of things that bring us less pleasure. That is akin to finding, in terms of our rats, that the rats enjoy the taste of the sweetened water more than the bitter water, but choose to regularly drink out of the bitter one instead, despite both options being available. It would be a very odd psychology that generates that kind of behavior. It would be the same kind of psychology that would drive rats in the enriched cages to leave them for the isolated morphine cages if given the choice; the very thing Johann is claiming would not, and does not, happen. It would require that some other force – presumably some vague and unverifiable entity, like “society” – is pushing people to make a choice they otherwise would not (which, presumably, we must change to be better off).

This moralization is worrying because it sheds some light on the motivation of the author: it is possible that evidence is being selectively interpreted so as to fit with a particular world view that has social implications for others. For instance, the failure to replicate I discussed in not new; it was published in 1996. Did Johann not have access to this data? Did he not know about it? Was it just ignored? I can’t say, but none of those explanations paint a flattering picture of someone who claims expertise in the area. When the reputations of others are on the line, truth can often be compromised in the service of furthering a social agenda; this could include people stopping the search for contrary evidence, ignoring it, or downplaying its importance.

A more profitable route research might take would be to begin by considering what adaptive function the cognitive systems underlying drug use might serve. By understanding that function, we can make some insightful predictions. To attempt and do so, let’s start by asking the question, “why don’t people use drugs more regularly?” Why do so many smokers wish to stop smoking? Why do many people tend to restrict most of their drinking to the weekends? The most obvious answer to these questions is that drinking and smoking entail some costs to be suffered at a later date, whether those costs be tomorrow (in the form of a hangover) or years from now (in the form of lung cancer and liver damage). Most of the people who wanted to quit smoking, for instance, cited health concerns as their reasons. In other words, people don’t engage in these behaviors more often because there are trade-offs to be made between the present and future. The short term benefits of smoking need to be measured against their long term costs.

“No thanks; I need all my energy for crack”

It might follow, then, that those who value short term rewards more heavily in general – those who do not view the future as particularly worth investing in – are more likely to use drugs; the type of people who would rather have $5 today instead of $6 tomorrow. They’d probably also be more oriented towards short term sexual relationships, explaining the interesting connection between the two variables. It would also explain other points mentioned in the Johann piece: soldiers in Vietnam using (and then stopping) heroin and hospital patients not suffering from addiction to their painkillers once they leave the hospital. In the former case, soldiers in war time are in environments where their future is less than certain, to say the least. When people are actively trying to kill you, it makes less sense to put off rewards today for rewards tomorrow, since you can’t claim them if you’re dead. In the latter case, people being administered these painkillers are not necessarily short term oriented to begin with. In both cases, the value of pursuing those drugs further once the temporary threat has been neutralized (the war ends/they end their treatment) is deemed to be relatively low, as it was before the threat appeared. They might value those drugs very much when they’re in the situation, but not when the threat subsides.

It would even explain why drug addiction fell when legalization and treatment hit Portugal: throwing people in jail introduces new complications to life that reduce the value of the future (like the difficulty getting a job with a conviction, or the threats posed by other, less-than-pleasant inmates). If instead people are given some stability and resources are channeled to them, this might increase their perceived value of investing in the future versus getting that reward today. It’s not about connecting with other people per se that helps with the addiction, then, as much as it’s about one’s situation can change their valuation of the present as compared with the future.

Such a conclusion might be resisted by some on the grounds that it implies that drug addicts, to some extent, have self-selected into that pattern of behavior – that their preferences and behaviors, in a meaningful sense, are responsible for which “cage” they ended up in, to use the metaphor. Indeed, those preferences might explain both why addicts like drugs and why some might fail to develop deep connections with others. That might not paint the most flattering picture of a group they’re trying to help. However, it would be dangerous to try and treat a very real problem of drug addiction by targeting the wrong factors, similar to how just giving people large sums of windfall money won’t necessarily help them not go broke in the long term.

References: Petrie, B. (1996). Environment is not the most important variable in determining oral morphine consumption in Wistar rats. Psychological Reports, 78, 391-400.

One comment on “The Drug Addictions Of Mice And Men

  1. Andreas on said:

    Your finding that addiction might be related to a general preference for short-term rewards over long-term rewards is not really opposed to the idea that a lack of social connection facilitates addiction.

    The psychobiologist Jaak Pansepp has stated that “social affect and social bonding are in some fundamental sense opioid addictions.” The opioid system is used to motivate social connection, and deprivation of social connection is an opioid deprivation. Drugs acting on the opioid system provide the soothing and relief that evolution has shaped us into demanding from our social environments.

    Yet, I think it would be foolish to state that all addiction is a “lack of love” as for instance Gabor Maté would have it. Alcohol addiction can be cured by the opioid antagonistic drug naltrexone, but it doesn’t quite have the same effect on nicotine addiction. At first it helps, but when they wear off naltrexone, the addiction resurfaces. There is something else going on–it’s not just a simple opioid conditioning phenomenon.

    To understand nicotine addiction, we must understand the habenula. Until recently, this epithalamic structure was woefully neglected. Then researchers began to realize that it may be the most important structure in the brain relevant to addiction. The lateral habenula is activated by pain and disappointment, and controls levels of dopamine, noradrenaline and serotonin in the brain. This is very interesting. Methylphenidates potentiate dopamine and noradrenaline activity in the brains of individuals with ADHD, and the result is enhanced self-regulatory abilities (“willpower”). Serotonin has by some researchers been dubbed the “willpower molecule” because it controls whether animals are able to ignore a smaller short-term reward in order to claim a larger long-term reward. And here we have a structure in the brain which controls both. Fascinating!

    Now what is the relation between serotonin, dopamine, and willpower? Researcher Okihide Hikosaka has suggested that dopamine reports changes in value states (better/worse), while serotonin reports global levels of value (good/bad). When you’re in a poor value state (depleted of resources, e.g. social connection), certain outcomes are better than uncertain outcomes–you can’t afford to take risks. So what happens? You prefer short-term rewards to long-term rewards.

    So I think it’s still meaningful to talk about a lack of social connection in addiction, while keeping in mind that it’s really desirable/undesirable biological value states that control short-term/long-term behavioral strategies.