Addiction is addiction is addiction, and dependency is dependency is dependency. In all cases, every time.
It's incredibly common for people to have at least one chemical dependency (in my case, sleeping pills), And it's incredibly common for people to have severe clinical depression for no reason at all. It isn't fair to say that those people should stay away from certain drugs. Sure, some people can have a bad reaction to marijuana, but that doesn't mean it's bad, or is always the case. I have Tourette's, chronic tics, and marijuana amplifies it. So I don't smoke it. That simple. But if it's the miracle drug for others, then great.
Sobriety is also a great addiction for some, and brings them to their best. Unfortunately, not everyone is so lucky.