The<unk>  (alternatively, stepping-stone theory, escalation hypothesis, or progression hypothesis) is a comprehensive catchphrase for the often observed effect that the use of a psychoactive substance is coupled to an increased probability of the use of further substances. Possible causes are biological alterations in the brain due to the earlier substance exposure and similar attitudes of people who use different substances across different substances (common liability to addiction). In 2020, the National Institute on<unk>  Abuse released a study backing allegations that marijuana is a<unk> " to more dangerous substance use, though not for the majority of people who use substances. A literature review by the United States Department of Justice found no conclusive evidence that the link is causal.
Gateway drug effect
Late effect
Bowditch effect
Acute toxicity
Fixed drug reaction
Abscopal effect
Side Effect
Haldane effect