Answer: Here is a brief description I have concluded;
The gateway drug effect (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).
Explanation: Hope this helps, have a terrific day! <3 Thanks are always appreciated!
In general, those who are passive don't speak up for themselves and let others "walk over them." Someone who is assertive will speak up and set healthy boundaries for themselves, but does this in a non threatening or harmful manner.