c5a18f9f__Drug_Policy_Reform___Glossary__Definition
[Term] Gateway / Gateway Theory [Definition] 
Theory suggesting a sequential pattern in involvement in drug use from nicotine to alcohol, to cannabis and then to “hard” drugs. In regard to cannabis, the theory rests on a statistical association between the use of hard drugs and the fact that these users have generally used cannabis as their first illicit drug. This theory has not been validated by empirical research and is considered out-dated.
Global Initiative for Drug Policy Reform » Glossary
Definition