People With Higher IQ’s Are More Likely To Use Illegal Drugs

Researchers have found that those with high childhood IQs are more prone to illegal drug use as adults. But what does this correlation really mean?

Two major papers have found a positive correlation between high childhood IQ and adult drug use.

The first was published in 2011 (Intelligence across childhood in relation to illegal drug use in adulthood: 1970 British Cohort Study). The second was published in 2012 (Intelligence quotient in childhood and the risk of illegal drug use in middle-age: the 1958 National Child Development Survey). Both were co-authored by James W. White PhD and all of the data for both research papers comes from The Centre for Longitudinal Studies (CLS), a research council operating from the Department for Quantitative Social Science, Institute of Education, at the University of London.

Perhaps it is the concept of intelligence that needs to be reconsidered in order to answer the question; IQ does not measure emotional intelligence or creativity.

Longitudinal studies observe variables over extended periods of time. Cohort studies are longitudinal studies of groups of people with shared characteristics or experiences; for example, the 1958 study follows the lives of 17,000 people born within the United Kingdom in a single week in 1958. The cohort is that group of 17,000 people. The CLS has done several such studies: in 1958, in 1970, another in 1989, and the Millennium Cohort Study of 2000-2001. All of these studies are, by definition, ongoing.

The CLS has provided data for publications on the most disparate topics: from the visual acuity of a national sample (Developmental Medicine and Child Neurology) to The Role of Breakfast Cereals in the Diets of 16-17-year-old Teenagers in Britain (Journal of Human Nutrition and Dietetics). Thus far, only the two aforementioned papers investigate a direct link between drug use and intelligence.

The 1958 cohort consists of 3,509 males and 3,204 females. All of the participants underwent cognitive ability testing at age 11. The test consisted of 40 verbal and 40 nonverbal items, created by The National Foundation for Educational Research in England and Wales, and was tried against other testing methods for validity. Cognitive ability scores were then “transformed into IQ equivalents to give a cohort mean of 100 and standard deviation of 15.” At the age of 42, participants were asked to complete a drug questionnaire. The questionnaire inquired about the use of cannabis, cocaine, amphetamines, ecstasy, LSD, amyl nitrate, psilocybin mushrooms, temazepam, ketamine, crack, heroin, methadone, and the fictitious drug semeron to identify false claims. Adjustments were made for socioeconomic background, material disadvantage, and antisocial behavior, though the study claims that “associations between IQ and most drugs were materially unchanged after these adjustments.” For men and women, one standard deviation increase in IQ scores (15 points) was associated with an increased risk of using all drugs with the exception of cocaine, amphetamines, ecstasy, and temazepam in men; ecstasy and temazepam in women.

While the strengths of this study are the size of the sample and the length of participant contact, there is limited data on the actual patterns of drug use. The 1958 cohort study lists a number of other studies which claim a correlation between IQ and generally good health practices such as lower rates of smoking, greater levels of physical activity, and increased intake of fruits and vegetables, which makes the link between IQ and drug use very curious: “These findings suggest that, in contrast to most studies on the association between childhood IQ and later health, a high childhood IQ may prompt the adoption of behaviors that are potentially harmful to health (ie, excess alcohol consumption and drug use) in adulthood” (1958 Cohort Study).

The 1970 cohort study differs slightly from the 1958 study in methodology. The 1970 study is the largest to date to examine childhood IQ and drug use, with 3,818 male participants and 4,128 female. At the age of five, researchers went to the participants’ homes and administered four tests of cognitive function: the Human Figure Drawing Test, a Copying Designs Test, the English Picture Vocabulary Test and the Profile Test. Scores were calculated and transformed into the IQ distribution (mean=100, SD=15). Intelligence was assessed a second time, at the age of ten, using a modified version of the British Ability Scales, and transformed into the commonly used IQ distribution.

At 16, participants reported on their level of psychological distress using a 12-item General Health Questionnaire, as well as their drug use, by way of simple yes or no questions. For example, “Have you ever tried taking cannabis?” The drugs on the questionnaire, street names included, were cannabis, cocaine, uppers, downers, LSD, heroin, and the fictitious semeron.

At the age of 30, participants were tested again on psychological distress and drug use. They also answered questions on educational achievement, salary, occupation, and social class. As in the 1958 cohort study, adjustments were made to account for psychological distress and socioeconomic background. It was discovered at the ages of 16 and 30 that both male and female participants who reported using illicit drugs had significantly higher childhood IQ scores.

Men who had used cannabis by age 16 had a mean IQ score of 109.65, men who had not had a mean IQ of 103.86. Men at 30 who had used multiple drugs within the previous 12 months had a mean IQ score of 104.72, men who had not had a mean IQ score of 101.69.

Women consistently showed greater correlation between IQ score and drug use. Women who had tried cannabis by age 16 had a mean IQ score of 107.74, women who had not had a mean IQ score of 101.42. Women at 30 who had used multiple drugs within the previous 12 months had a mean IQ score of 108.85, women who had not had a mean IQ score of 100.31.

The study suggests that greater intelligence is associated with novelty seeking, “A possible pathway that emerges from the literature on personality is that high IQ individuals have also been shown to score highly on tests of stimulation seeking and openness to experience.”

Though no specific studies are cited linking intelligence and stimulation, it isn’t difficult to find literature that supports these claims. Stimulation Seeking and Intelligence: A Prospective Longitudinal Study published in the Journal of Personality and Social Psychology in 2002, asserts that it is the first study to show a link between between stimulation seeking and intelligence, hypothesizing that stimulation seekers are looking to create an enriched environment for their cognitive development.

If it is true that higher intelligence correlates with stimulation seeking behaviors, the question that follows is why. Some evolutionary psychologists attempt to explain the motivation behind the desire to grow intelligence through stimulation and novelty, claiming that it was an evolutionary imperative to be able to solve new problems, and thus people with greater intelligence are drawn to the novel. One evolutionary psychologist has made a name for himself online making such claims.

Why Do Intelligent People Use More Drugs?

Satoshi Kanazawa is an author and evolutionary psychologist at London School of Economics. He is also the controversial character who was dismissed from Psychology Today for writing the insubstantially supported article Why are Black Women Less Physically Attractive than Other Women. He wrote Why Intelligent People Use More Drugs for the Psychology Today website, arguing The Savanna Principle, which he developed.

The principle is built upon the evolutionary psychology concept of EEA – environment of evolutionary adaptedness. EEA states that human evolution occurred mainly in the Pleistocene era, which ended about 12,000 years ago. The argument is that human brains are wired to deal with life as it would have been during the Pleistocene era. Kanazawa’s Savanna Principle asserts that human development evolved during the Pleistocene era on the African Savanna, and that any reasonable hypothesis about human behavior must incorporate the EEA. Although the link can be made between IQ and drug use, given the cohort studies; and the link can be made between IQ, drug use, and novelty given the cohort studies coupled with the longitudinal study published in 2002; the link cannot be reliably made between novelty seeking behaviors and evolutionary progress.

However popular Kanazawa’s theory that intelligent people use drugs because drugs are recent stimuli in respect to human evolution, it is unproven and according to critics of evolutionary psychology, untestable. While the EEA argument applied to novelty and drug use cannot be dispelled, it also cannot currently be proven, and seems somewhat dismissive of the myriad of socioeconomic and cultural variables, that, try as the researchers might, cannot be eliminated from intelligence testing, and/or the world in which people take illicit drugs.

Theories for the Correlation

Several other theories on why high childhood IQ can be linked to drug use in adolescent and adult life have been posited by both the authors of the cohort studies as well as those who report on their findings. Clinton B. McCracken’s emotional opinion piece, Intellectualizing Drug Abuse, details his very real experience as a high functioning professional whose life is undone by drug use. McCracken cites the high rates of drug use amongst healthcare professionals, first noting their access to illicit materials, second their ability to intellectualize their drug use. Intellectualization differs from rationalization and denial (the latter two are often regarded as common attitudes towards substance abuse, unaffected by education or training) in that it relies upon training and knowledge. McCracken was a biomedical scientist well aware of the criteria required to deem one an addict; careful to stay away from textbook examples of abuse and criminal behavior. This is how the intellectual maintains the illusion of control or mastery. He states:

“The transition from my drug use having no apparent negative consequences, to both my personal and professional life being damaged possibly beyond repair, was so fast as to be instantaneous, highlighting the fact that when it comes to drug use, the perception of control is really nothing more than illusion.”

While intellectualization of drug use seems reasonable, it too is just a theory. Perhaps something as simple as boredom and isolation could provide the answer. Studies have long since linked extremely high IQs and social maladjustment (Factors in the Social Adjustment and Social Acceptability of Extremely Gifted Children, Ohio Psychology Press, 1994). Is it possible that isolation makes one susceptible to substance abuse? If you’re a rat, it does. Researchers at the University of Texas found that isolated rats show greater preference for drug rewards and higher addiction rates than the non-isolated rats. The isolated animals are more sensitive to reward and become more malleable, and more easily addicted than their non-isolated counterparts. While it seems possible that the isolation of those with higher intelligence may create a more dependent mindset, two flaws in this argument arise when using it to explain drug use and high IQs. The loneliness and isolation apparent in gifted children generally appear in those with an IQ of 170+, which is so far outside of the mean that it hardly applies to the data of the British cohort study. Second, we aren’t rats.

Emotional Intelligence

If not overconfidence, if not isolation, what drives highly intelligent people towards drug use? Perhaps it is the concept of intelligence that needs to be reconsidered in order to answer the question. IQ does not measure emotional intelligence or creativity. Emotional intelligence was defined and popularized by Daniel Goleman in his book Emotional Intelligence – Why it can matter more than IQ (1995). It is said to encompass impulse control, perseverance, diligence, motivation, empathy and social skills; the ability, competence, and skill set to cope with challenges and achieve success. There is a significant amount of research linking low emotional intelligence with drug abuse (Low Emotional Intelligence as a Predictor of Substance-use Problems, Journal of Drug Education, 2003). Although there is a tendency to regard a high IQ as a precursor to success and achievement, nowhere within the IQ score is contained the assessment of the ability to make good decisions, or to use common sense. Although low emotional intelligence is linked with drug abuse, the British cohort studies contain no data regarding patterns of drug use and it would be difficult to make a definite link between high IQ, low emotional intelligence and drug use and/or abuse.

IQ does not measure emotional intelligence or creativity. Nor does it measure cultural impact on learning, adaptation, or identity. Critics of IQ testing note the lack of cultural variability within the tests. While the tests are meant to serve as a tool for assessing intelligence across all cultures, the disparity in scores between ethnic groups cannot be explained without adding the element of culture. We are complex organisms, we live in an interdependent world. To isolate intelligence from other factors is to alter reality. We learn holistically. Our intelligence is elastic and works when there is an environment for it to work within. While the data may be statistically significant, and those who score higher on standard ability tests are more likely to use drugs, perhaps we should consider the culture that these novelty seekers exist within. There has been some discussion on culture and drug use, though usually with such a macro lens on society, government policy, and social trends, that more subtle factors are missed.

“Most culturally distinct groups have used and abused alcohol and other drugs throughout the ages, and they have established codes of behavior in their approach to drugs and alcohol” (Culture and Substance Abuse: Impact of Culture Affects Approach to Treatment, Psychiatric Times, 2008).

A culturally distinct group can be a nation, or a culturally distinct group can be motorcycle gang, a rowing team, a gaggle of freaks. Each group has their own codes of behavior and the way to show loyalty to a group is to adhere to that behavior. It is intelligent to adapt. Drug culture of the 1960s would certainly have affected the participants of the 1958 cohort, just as rave culture in the 90s would have an impact on the attitudes of participants of the 1970 cohort. Surely social movements, their celebrities, and use of drugs in popular culture influence the intellectual drug user.

So, whether novelty, intellectualization, isolation, or aestheticization, something drives intelligent people to seek thrills, escape, or identity in illicit substances on a statistically significant basis.