Reading descriptions of the lives of people living in adverse economic conditions, something that will strike you over and over again is how often addiction comes up: to alcohol, to tobacco, to other drugs, or to behaviours such as gambling. There is addiction in all strata of society, but, from the novels of Zola to today, it seems specially prevalent where people have the least access to money and power. Is this really true, and, if so, how could we possibly explain it?
Epidemiological evidence confirms that it is really true. In the USA, the prevalence of smoking is about twice as high amongst those in routine/semi-routine occupations compared to managers and professionals. Smokers of all classes try to quit; managers and professionals are more likely to succeed. Addictive substances often show double dissociations with class: people with more money can afford to consume more of the substance, since they have more money; but people with less money are more likely to end up consuming to the point where it causes them life problems. So, for example, higher-SES young people in France consume more cannabis overall; but lower-SES young people are more likely to be frequent users. The double dissociation is particularly clear for alcohol. In many studies, it is people of higher SES who consume more alcohol on average, but people of lower SES who are most likely to die from the consequences of alcohol. As for behavioral addictions, the companies that run gambling machines know where to put them: in the areas of the highest economic deprivation.
Yes, addiction is related to poverty. But so are many other things. The existence of socioeconomic gradients is such a pervasive feature of affluent societies that it extends to almost everything you can measure. Is addiction more steeply related to income than other things? The only evidence for this that I have been able to find comes from the study of alcohol-related mortality. People of lower SES are more likely to die from the consequences of alcohol; but of course they are more likely to die tout court. Probst et al. meta-analysed studies that compared the SES difference in alcohol-attributable mortality to the SES difference in overall mortality in the same populations. They concluded that the high-low SES differences in alcohol-related mortality were typically 1.5-2 fold larger than the high-low SES differences in mortality overall.
Let’s assume that these gradients reflect something about poverty causing increased addictive behaviour (not of course an easy thing to demonstrate, but I’ll come back to that at the end). How can we explain why?
First, we need to characterise what kinds of substances and activities can create addiction. Jim Orford, in his wide-ranging book Power, Powerless and Addiction suggests that things can be addictive if they (a) have the capacity to produce a short-term boost in mood; (b) they can be consumed frequently in small chunks; and (c) they entrain processes that tend to increase their own consumption over time. If you focus on (a) and (b), the socioeconomic gradient seems very intelligible. In the flow of everyday experience, people facing greater economic adversity are often in worse mood (there is abundant evidence that this is true, and there are good reasons for it); and, plausibly, they have less access to alternative mood-boosting inputs that come with affluence and high status.
There are other bodies of thought we can draw on to fill out this idea. There is the ‘rational addiction’ tradition that comes from economics. The essence of this idea is that people might, under some circumstances, choose to consume an addictive substance, even in the full knowledge that this will lead to future dependence. They will do so when it maximises their long-term utility; in other words when the value they place on all the mood boosts they will get outweighs the disutility of the present and future costs of use. The literature on rational addiction has got a bit bogged down in some rather inside-baseball issues, such as whether people reduce consumption in response to price rises that have been announced but not implemented yet. This is an important test because it establishes whether they are considering future consumption, not just present consumption, in their decisions to consume; but it distracts from the more general insights the rational addiction model might provide.
As often with rational actor models, the rational addiction model seems like a kind of useful fiction. On one hand it is obviously false. People usually don’t make those computations, certainly not explicitly. Plus, the rational addiction model in its original form cannot account for the fact that people constantly try to quit, often without success; or that they spend money on having other people force them to stop them from consuming . To explain these phenomena, you need to add something call time-inconsistent preferences, namely that what I value happening at time point t flips as t approaches the present. On the other hand, the rational addiction model is many-fold better than unhelpful and non-explanatory appeals to ‘lack of self-control’ or ‘the culture of poverty’. It sees people who consume as full and normal agents, albeit agents constrained by the option sets available to them. Those option sets are often not great. In poverty, either the marginal benefits of addictive consumption might be higher (because your mood is often worse and this makes it boosting it more valuable), or the opportunity costs of addictive consumption are lower (for example, the job you could lose is awful anyway, or there is no prospect of ever converting the cigarette money into owning a house).
A related and useful literature is that on pain and analgesia. Addictive substances tend to be analgesic: they reduce pain. Much of the drug addiction in the USA and other developed countries involves opioid drugs. These are so effective at pain relief that they have long been used in surgery. Indeed, it was their approved medical use that lies at the root of the iatrogenic addiction crisis. What is less well known is that alcohol, nicotine and cannabis all have fairly well-studied analgesic effects. It is not a metaphor when people say they drink or smoke to ease the pain.
Pain is socioeconomically distributed. There’s evidence of socioeconomic gradients in severe pain in Austria, and dental pain in the UK. Physical pain and emotional pain are on the same continuum (anti-inflammatories like ibuprofen reduce depressive symptoms after all), and I wager that emotional pain shows at least as much of a gradient as physical pain does, probably more. Studies conclude that the socio-economic gradient of pain is currently unexplained; but perhaps, in fact, its explanation is all too obvious. Pain is the unpleasant experience associated with the appraisal that you are being damaged. The ability to feel pain is there for a reason. If you can get out of the painful situation, you will. But if you have no alternative but to go on being damaged, then self-medication looks like the next best thing.
If poverty causes pain and low mood, then really there is no mystery to the fact that people in poverty rely more heavily on mood-boosters. Property (c) of addictive substances – they catalyse their own use – is still a problem. But you can see why it is easier to start and more difficult to stop if you face poverty and adversity. This leads to the simple prediction that increasing people’s incomes will reduce their consumption of analgesic-addictives.
What I love about this prediction is how counter it runs to most people’s intuitions. When Nicaragua introduced an direct cash transfer programme, a senior official predicted that “husbands [would be] waiting for wives to return in order to take the money and spend it on alcohol“. A brake on the introduction of cash transfers in Kenya was “the widespread belief that cash transfers would either be abused or misdirected in alcohol consumption“. Does the evidence back up these intuitions?
Reader, it does not. For the World Bank, David Evans and Anna Popova reviewed all the studies that they could find looking at the impact of a change in income on either consumption of or expenditure on alcohol and tobacco. They concluded that “almost without exception, studies find either no significant impact or a significant negative impact of [cash] transfers.” Restricting the analysis to the 17 estimates that came from randomized control trials, 14 went in the negative direction, and the 3 in the other direction were small. It’s worth thinking about how strong a test this is. Some people, who were generally in low and middle income countries and had strong financial constraints, were suddenly given higher incomes to spend. It’s not just that they did not use it to increase their expenditure on these addictive goods. They more often than not decreased it. Doing social science, I have heard it said, is the search for the small set of things that is both surprising and true. I would add, surprising, true, and makes a difference. It would be good if this were one of that set.