Does Scottish poverty cause drug use?

A few months back, The economist had an article about the drugs problem in Scotland. This statistic caught my attention:

Scots in the poorest areas are sixteen times more likely to die from a drug-related death than Scots in the richest areas.

The difference between overdose death rates among the rich and the poor is too great to be attributed to mere chance. This discrepancy cries out for some kind of explanation.

One possibility is that a lack of money makes people depressed, and that depressed people are more likely to use drugs to ease the pain of poverty. Another possibility is that both poverty and drug abuse are caused by a third factor. How can we distinguish between these alternative theories?

The same Economist article contains a graph showing some equally surprising differences in drug overdose rates between countries:

There appears to be little or no connection between the wealth of countries and the rates of drug abuse. Scotland’s GDP per capita is right on the European Union average, the US is much richer than the European average, while Portugal is much poorer than average. And yet it is Portugal that has the lowest number of drug overdose deaths.

How can we reconcile the fact that drug abuse in a country like Scotland is highly correlated with income, while internationally there is little evidence that poverty causes drug abuse? One possibility is that both drug abuse and poverty are caused by a third factor.

Suppose that both poverty and drug use are correlated with some aspect of personality. Also assume that all countries have a mix of personalities, some of which are more prone to drug use than others. And finally, assume that international differences in per capita income are not caused by differences in national personalities. I am not suggesting that these assumptions are entirely true. Rather, I argue that they allow us to understand why drug use may be strongly correlated with poverty within a given country, but not across countries.

If we assume that in both poor and rich countries a fairly stable percentage of the population has a personality that predisposes them to drug abuse, then we should not necessarily expect more drug abuse in poor countries than in rich countries. If we also assume that the same aspect of personality that leads to drug abuse also leads to poverty (let’s say a lack of self-control), then we can explain both the within-country correlation and the lack of international correlation.

Case closed? Not quite. This does not explain why there is such a large difference in the number of drug overdose deaths between different countries (and even between different regions, as we see in Britain). There is something else going on, but poverty alone does not seem to be a solution. explanation.

One possibility is that some countries have legal systems that are more tolerant of drug use. But that also appears to be inconsistent with the data, as both Switzerland and Portugal rely more on a softer “harm reduction” approach, while the US and Scotland have much stricter enforcement of anti-drug laws. In fact, strict enforcement of drug laws may actually increase overdose deaths by creating an underground market where the quality of the drugs is extremely unreliable.

Instead, I suspect that drug use is correlated with two factors: personality and regional culture. In regions of the world where people do not have community support systems, drug abuse may be higher, and people with certain personality types may be more likely to use drugs within a given area. The worst situation of all would be for people who lack self-control and live in relative isolation in countries without strong support systems for individuals struggling with life.

In the US, these are the two states with the lowest rates deaths from drug overdose are Nebraska and South Dakota. Both states have many small rural towns with a strong sense of community. North Dakota was quite similar culturally, but the fracking boom in the Bakken region has brought in many younger workers isolated from their families and communities. North Dakota still has a fairly low rate of drug overdoses, but it is now significantly worse than its two neighbors to the south. And yet no one would argue that the oil boom has made North Dakota poorer—in fact, the opposite is true.

In conclusion, poverty is probably not the direct cause of drug overdose deaths. But within a given region, the factors that cause poverty likely correlate with the factors that cause drug abuse.