Basic Trope: The use of drugs is portrayed in a manner that plays up their negative effects and downplays their positive ones, usually for the sake of setting up and delivering An Aesop against drug use.
Straight: Billy smokes a joint, and starts ignoring his schoolwork and committing petty thefts. His parents find out, and Billy delivers An Aesop about how drugs ruin lives.
Exaggerated: Billy smokes a joint and kills his family because he hallucinates that they're all giant mice with chainsaws. The drug is also why his first impulse is to attack them rather than to run away from them.
Downplayed: Billy smokes a joint. He finds its effects unpleasant and decides not to smoke again.
Justified: Billy becomes overpowered by his drug use in the way that he does in the straight example, but his doctor explains that it only had such a profound effect on him because of his pre-existing psychological imbalances.
Inverted: Billy's brother Jack has suicidal depression which suddenly disappears when he takes a pill, and does not come back even when its effects wear off; drugs are subsequently portrayed as the ideal, consequence-free solution to all his problems.
Subverted: Billy drinks ten beers, borrows his father's car, and crashes it into a lamp-post. It's then revealed that the beer was non-alcoholic.
Double Subverted: ...though the joint he was smoking at the time was quite potent indeed.
Zig Zagged: When Billy takes drugs, he drives into a tree and ends up hospitalized. Except that it turns out they were fake. But then he finds out that the coffee he drank afterward was spiked. And then he learns that his accident was actually engineered by his arch-nemesis to try to kill him, and only his unbalanced mindset stopped him from behaving exactly how they predicted.
Averted: Billy smokes a joint and proceeds to have a good time with his friends, although he feels a bit sketchy and paranoid after a while.
Enforced: The government is cracking down on cannabis in a big way, and the Aesop is shoehorned into the show at their request. (This is the case with more than a few straight examples.)
Lampshaded: Billy holds the joint aloft, as if making a toast, and says, "Here's to a perfectly good life, ruined with a single puff." He inhales anyway.
Defied: After smoking the joint, Billy makes a point of ignoring all the possibilities for misdeeds that present themselves to him at every turn, determined to prove that drugs will not lead him down that path.
Discussed: Billy smokes a joint. His concerned friend tells him that this never ends well in television programs.
Conversed: Billy smokes a joint while watching an episode of a Show Within a Show in which Norbert is smoking a joint. He rolls his eyes, commenting "Oh great, another Very Special Episode."