Synapses are able to change strength and function when a pathway is stressed, overused, or underused, such as by the intake of psychoactive substances

This is a true statement.

This statement describes a very important ability of the synapses called synaptic plasticity. These changes can last from weeks to years and it has been observed that the younger the user the more probable that the changes will remain. This is the reason that some chronic users find it very difficult to recover from the drug abuse.