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.