Finding out about the risk factors for drug abuse and understanding why some people are more prone to addiction than others is a valid priority for addiction research, but the associations observed aren’t always so easy to explain. Studies that have found an association between high IQ in childhood and drug use run contrary to many other findings about the generally positive approach more intelligent people take when it comes to their own health behavior. This disparity is a puzzling one, but several experts have proposed explanations as to why it may exist.
The most significant findings regarding the link between childhood IQ and subsequent drug use come from two longitudinal cohort studies published in 2011 and 2012. These long-term studies started in 1970 and 1958, respectively, and numerous pieces of research have been conducted based on the original samples. To investigate the relationship between childhood intelligence and drug use, 3,509 males and 3,204 females were used from the 1958 sample. The group was given cognitive testing at age 11, and the results were converted into IQ scores. When the participants were 42, they were given a questionnaire about their drug use, including questions about their use of numerous substances as well as “semeron,” a made-up substance included to catch people who were lying about their drug use.
For the 1970 group, researchers used 3,818 males and 4,128 females to look at the link between childhood IQ and later drug use. They gave the participants four cognitive function tests at age 5, and the participants were tested again at age 10 (using a different method), and both of these were converted into IQ scores. The drug use questionnaires were conducted at ages 16 and 30, and these tests also incorporated questions to help determine participants’ levels of psychological distress, an important factor in determining later drug use. The questionnaire included the fake drug again, for the same reason, but covered fewer specific substances than the 1958 group’s questions.
Higher IQ, Higher Risk Of Drug Abuse
Generally, both of the studies found that higher IQ was associated with an increased likelihood of drug use. The 1958 test showed that an increase in IQ of 15 points (statistically defined as the “standard deviation” in IQ score) was associated with a greater chance of using all drugs covered in the research, with the exception of ecstasy and temazepam in both men and women, and also cocaine and amphetamines in men. The large sample size in this study gives some strength to the findings, but if more information was obtained about the patterns of subsequent drug use, it would have undoubtedly helped to paint a clearer picture of the effects of high childhood IQ.
The 1970 group found significantly higher IQ scores in the drug-using participants at both 16 and 30 years of age. For men, the average IQ for those who hadn’t used marijuana at age 16 was 103.86, whereas for those who had, it was 109.65. At age 30, male participants who hadn’t used multiple drugs in the previous year had an average IQ of 101.69, but for those who had, the average was 104.72. For women, the corresponding figures showed notably larger associations, with women who had tried marijuana by age 16 having an average IQ of 107.74 compared to 101.42 in those who hadn’t. For use of multiple drugs in the past year at age 30, women who hadn’t used multiple drugs had an average IQ of 100.31 and those who had recorded an average IQ of 108.85.
These are all statistically significant differences, which persisted after distress had been accounted for, meaning that it wasn’t due to chance variation or differences in childhood distress levels—there really seems to be a difference in the likelihood of drug use depending on childhood IQ.
Why Would Intelligent Kids Be More Likely To Use Drugs?
The findings are puzzling because on other measures of healthy living—abstaining from smoking and eating more fruit and vegetables, for example—intelligent people seem to care more about their health. There have been several theories proposed to explain this difference. One of the most convincing ideas comes from an issue with the use of IQ tests. These are known to be culturally biased, but the most relevant issue when it comes to later drug use is that they don’t measure emotional intelligence, which incorporates things like impulse control and the ability to deal with problems. Low emotional intelligence has been associated with drug use in the past, and while these studies can’t be interpreted in this way (because they don’t consider emotional intelligence) it could be that this is driving the relationship. Alternatively, it’s been suggested that intelligence breeds isolation, which in turn makes drug use more likely, as is shown in rat models of addiction.
Regardless of the reason for the observed difference, the fact that it exists means that there is something both addiction experts and parents can look out for. Even without it being thoroughly understood, if your child is intelligent, it’s worth talking to him or her about drugs, particularly focusing on how drug use is an unhealthy method of dealing with emotional or personal problems. More importantly, it’s essential we let these intelligent kids know that somebody is there to talk to them if they do run into problems, so anything that does emerge won’t go unchecked for long.