A 2011 study conducted on nearly 8,000
people measured their IQ scores at ages 5 and 10. Then, the study followed up with these individuals at ages 16 and 30. Individuals from this group with higher IQ scores were more likely to use cannabis, cocaine, ecstasy, amphetamines, or a combination of these
drugs. Women with IQ scores in the
top third, for instance, were more than twice as likely to have used cannabis or cocaine by 30 than those in the
bottom third. Men with high IQs were nearly twice as likely to have taken amphetamines and 65 percent more likely to have taken ecstasy compared with men who scored less.