"The following graph shows the association between childhood general intelligence and the latent factor for the consumption of psychoactive drugs, constructed from indicators for the consumption of 13 different types of psychoactive drugs (cannabis, ecstasy, amphetamines, LSD, amyl nitrate, magic mushrooms, cocaine, temazepan, semeron, ketamine, crack, heroin, and methadone).  As you can see, there is a clear monotonic association between childhood general intelligence and adult consumption of psychoactive drugs.  “Very bright” individuals (with IQs above 125) are roughly three-tenths of a standard deviation more likely to consume psychoactive drugs than “very dull” individuals (with IQs below 75)."