Explanation why characters are physically and psychologically addicted

There were a couple of clarifications needed for my transmission before.
The example of a drug abuser, which was the american doctor, was physically and psychologically addicted to morphine. Morphine is a highly addictive drug that creates strong withdrawal effects when the dosage is reduced or stopped. The doctor developed a psychological dependency, as he thought it was the only way to feel free of stress
The drug misuser example didn't really have strong addictions as she needed painkillers for the treatement and simply overdosed her painkillers after a psycological shock
The recreational Marijuana-using student however, was in a way, addicted to Marijuana. He wan't necessarily addicted physically but he was psychologically addicted to a degree. He relates to Marijuana as a pleasurable experience and this causes him to return to Marijuana without any sense of guilt.

Dora