Gateway drug effect
The gateway drug effect (alternatively, stepping-stone theory, escalation hypothesis, or progression hypothesis) are terms denoting the hypothesis that the use of a psychoactive substance is coupled to an increased probability of the use of further substances. Possible explanations for this connection include environmental influence, personality traits that favour seeking both soft and hard drugs, alterations in the brain due to earlier substance exposure, as well as similar attitudes of people who use different substances, and therefore experience a "common liability to addiction".