High IQ in Childhood May Increase Risks for Illicit Drug Use in Adulthood
In recent decades, researchers and mental health experts have made extensive progress in uncovering the basic nature of substance abuse and addiction. In part, their conclusions show that, over time, abuse and addiction affect the body in ways that are highly analogous to the effects of chronic diseases such as heart disease and diabetes. Still, despite these findings, people with abuse- or addiction-related issues are sometimes stereotyped in society as morally weak or somehow mentally deficient. Despite these stereotypes, current evidence shows that people with low IQs don’t have especially high risks for illicit drug use. In fact, high childhood IQ score-not low scores-appear to be associated with increased risks for illicit drug use in adulthood.
IQ Score Basics
IQ stands for intelligence quotient, a term created in the early 1900s by a German psychologist named William Stern. Initially, IQ testing was designed to measure a child’s “mental age,” and then compare this age to the child’s actual chronological age. However, modern testing measures the performance of both children and adults on specially designed tests, then compares the results against the performance of a nonexistent, virtual person who represents the average intelligence of the entire population within a certain age group.
This average level of performance is always adjusted to equal 100 IQ points; generally speaking, testing results above this average rank as relatively high IQ scores, while testing results below this average rank as relatively low IQ scores. Roughly 70 percent of all people have an IQ score between 85 and 115, while fully 95 percent of all people have an IQ score between 70 and 130. Still, there are several different IQ testing formats in use, and these formats differ in certain relatively minor respects; as a result, people commonly get slightly different scores when taking various versions of the test. The outcomes of IQ testing are frequently used to predict such things as future academic performance, likelihood of involvement in special education programs, future job performance and future earning potential.
Childhood IQ As a Drug Use Predictor
In 2011, researchers from Cardiff University in Wales, UK, examined IQ results from an ongoing, long-term study-called the 1970 British Cohort Study-that is following thousands of British citizens from their birth in 1970 through adulthood and into old age. First, they looked at scores of IQ tests that study participants took at the age of five and then compared these scores to the results of testing done when study participants were age 10. Next, the Cardiff University researchers took these childhood IQ scores and compared them to study participants’ adult usage patterns for the illicit substances marijuana, Ecstasy (MDMA), cocaine, and illegal amphetamines (speed). They also traced adult participation in polydrug use, which involves simultaneous or nearly simultaneous use of two or more substances.
Out of all participants in the 1970 British Cohort Study, those with high IQ scores at ages five and 10 had the highest overall rate of illicit drug use at both age 16 and age 30. Specifically, when compared to men who had lower-than-average childhood IQ scores, men with high childhood IQ scores used Ecstasy about 65 percent more frequently and illegal amphetamines roughly 50 percent more frequently; these men also engaged in polydrug use almost 60 percent more frequently. When compared to their counterparts with relatively low childhood IQ scores, women with high childhood IQ scores had more than double the usage rates for both cocaine and marijuana. While the British Cohort Study is not necessarily definitive for illicit drug use in all settings or circumstances, it presents an unusually extensive, long-term view of real-world life outcomes among a broad population group.
No one knows for sure why high childhood IQ seems to increase the likelihood of adult drug use. However, Psychology Today explains, relatively intelligent people seem to value new and unique experiences more than relatively “unintelligent” people, and have a greater tendency to explore life beyond society’s established norms. It’s important to note that the British Cohort Study did not measure frequency or quantity of adult drug use, and no one knows if high childhood IQ predicts these aspects of drug involvement. Still, logically speaking, people who experiment with drugs have greater chances of developing substance abuse problems than people who don’t experiment with drugs. For this reason, abuse and addiction issues may appear in precisely those people who, according to outdated social norms, “would never do drugs.”