Has there ever been a case where something like #2 has happened?
Don't think you need to worry about that one.
There are some evidence that Ozempic/Wegovy actually cures more addictions than just food addiction.
>The weight-loss jabs have apparently helped people kick habits from smoking to shopping, although scientists remain wary about recommending it as an addiction treatment
https://www.theatlantic.com/health/archive/2023/05/ozempic-a...Sure: the popularization of coffee across western Europe in the 1600s and 1700s, and the way it replaced beer as the most common daytime casual drink. Much of the population went from spending all day mildly intoxicated to being mostly sober and with a caffeine pick-me-up.
Some athletes (especially weightlifters) use Tadalafil, an erectile dysfunction drug, because it also promotes bone density and muscle growth while having few observable side effects. This isn't really surprising, it's basically just a mild vasodilator. A better known drug in the same class Sildenafil (aka Viagra) is less mild, and associated with retinal damage if overused.
Adding iodine to salt has greatly increased the population's IQ in countries that have adopted it.
https://pubmed.ncbi.nlm.nih.gov/15734706/