What"s prescription is here, may not be prescription somewhere else (canada vs. u. s. ) Codeine is an over the counter drug here. Used socially don"t need to go to a drug store. Not produced commericially like marijuana, lsd, cocaine. Or they"re produced commericially but not for their psychoactive affect. Airplane glue is produced commericially but made to put airplanes together, not to sniff and get high. If a drug is taken repeatedly, you get a reduced behavioural effect. Most drugs show this behavioural phenomenon known as tolerance. Assumption is that when you repeatedly take a drug, the brain tries to compensate for this by changing the sensitivity or number of receptors that are affected. Brain adapts plasticity occurs you"re overstimulating by taking drugs. It"s the exact opposite since depressants slow the brain down. Small amounts of it thereforeonly produces normal level of activation.