> "It's not like drug addiction is a thing that happens to you"

A common route that leads people to taking heroin is...

1. Go to the doctor, get prescribed pain medication.

2. Become addicted to pain medication during treatment.

3. After supply of pain medication dries up, turn to illegal alternatives (which includes heroin).

So it really could happen to anyone, as it's possible to become an addict without any prior intention to take illegal substances.