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Tuesday, November 15, 2011

Smart Kids Use More Drugs? Research

Who would have thunk it?

"A new British study finds children with high IQs 
are more likely to use drugs as adults 
than people who score low on IQ tests as children."  

(Jennifer Bixler, "High IQ Linked to Drug Use," CNN News,, November 14 2011)

This data come from the 1970 British Cohort Study, which has been following thousands of people over decades.  The kids' IQs were tested at the ages of 5, 10 and 16.  The study also asked about drug use and looked at education and other socioeconomic factors.  Then, when participants turned 30, they were asked whether they had used drugs such as marijuana, cocaine heroin, amphetamines, ecstasy, LSD, hallucinogenic mushrooms, and crack in the past year. (Dr. James White, "Intelligence Across Childhood In Relation To Illegal Drug Use In Adulthood: 1970 British Cohort Study, Journal of Epidemiol Community Health, November 14 2011)

The study defined high IQ as a score between 107 and 158 and an average IQ is commonly known as 100.

The authors used data from a large population-based birth cohort with measures of lifetime cannabis and cocaine use, parental social class and psychological distress at 16 years; cannabis, cocaine, amphetamine, ecstasy and polydrug use (more than three drugs) in the past 12 months; and social class, educational attainment and gross monthly income at 30 years. All members of the cohort with IQ scores at 5 or 10 years were eligible to be included in the analyses.

Findings in the study:

1. By the age of 30, around one in three men (35.4%) and one in six women (15.9%) had used cannabis, while 8.6% of men and 3.6% of women had used cocaine, in the previous 12 months.

2. A similar pattern of use was found for the other drugs, with overall drug use twice as common among men as among women.

Now, factor in intelligence:

3. Men with high IQ scores at the age of 5 were around 50% more likely to have used amphetamines, ecstasy, and several illicit drugs than those with low scores, 25 years later.

4. Women with high IQ scores were more than twice as likely to have used cannabis and cocaine as those with low IQ scores.

5. The same associations emerged between a high IQ score at the age of 10 and subsequent use of cannabis, ecstasy, amphetamines, multiple drug use and cocaine, although this last association was only evident at the age of 30.

6. The findings held true, irrespective of anxiety/depression during adolescence, parental social class, and lifetime household income.

"Although most studies have suggested 
that higher child or adolescent IQ prompts 
the adoption of a healthy lifestyle as an adult, 
other studies have linked higher childhood IQ scores
to excess alcohol intake and alcohol dependency in adulthood," write the authors.

Why the Link Between High Childhood IQ And Illicit Drug Use?

"We suspect they may be more open 
to new experiences 
and are more sensation seeking," says White.

The authors point to previous research, showing that highly intelligent people are open to experiences and keen on novelty and stimulation.

Other research has also shown that brainy children are often easily bored and suffer at the hands of their peers for being different, "either of which could conceivably increase vulnerability to using drugs as an avoidant coping strategy," explain the authors.

The following graph shows a similar association between childhood intelligence and the latent factor for the consumption of psychoactive drugs among Americans.  The data come from the National Longitudinal Study of Adolescent Health.  The childhood intelligence is measured in junior high and high school, and the adult drug consumption is measured seven years later, and constructed from indicators for the consumption of 5 different types of psychoactive drugs (marijuana, cocaine, LSD, crystal meth, and heroin).  The association is not monotonic, but nevertheless, “normal” (90 IQ & 110), “bright” (110 IQ & 125), and “very bright” individuals consume more psychoactive substances than “very dull” or “dull” (75 IQ & 90) individuals.

(, "Why Intelligent People Use More Drugs," The Scientific Fundamentalist, October 31 2010)

"The human consumption of psychoactive drugs, 
such as marijuana, cocaine, and heroin, 
is of even more recent historical origin 
than the human consumption of alcohol or tobacco, 
so the Hypothesis would predict that more intelligent people
use more drugs more frequently than less intelligent individuals."

("Why Intelligent People Tend To Use More Drugs,"

The use of opium dates back to about 5,000 years ago, and the earliest reference to the pharmacological use of cannabis is in a book written in 2737 BC by the Chinese Emperor Shen Nung. Opium and cannabis are the only “natural” (agricultural) psychoactive drugs. Other psychoactive drugs are “chemical” (pharmacological); they require modern chemistry to manufacture, and are therefore of much more recent origin. Morphine was isolated from opium in 1806, cocaine was first manufactured in 1860, and heroin was discovered in 1874.

"The fact that the consumption of psychoactive drugs 
has largely negative health consequences
and few (if any) benefits of any kind 
is immaterial to the Hypothesis. 
It does not predict that more intelligent individuals 
are more likely to engage in healthy and beneficial behavior, 
only that they are more likely to engage in evolutionarily novel behavior." 

("Why Intelligent People Tend To Use More Drugs,"

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