There are a lot of questions people have that the show doesn't really explain. Overall the show was kind of a let down because of this. I would recommend you don't read into anything too much.

I think it gets to call the shots at that point.

The study you're referring to was done by Irving Kirsch. He's an American psychologist who specializes in the placebo effect. He found that antidepressants have no clinical significance when compared to a placebo while like you said exposing people to a host of terrible side effects.

Different stains definitely have different effects on me. But a couple hours after I smoke and begin that comedown phase, I usually always get sleepy. Even if it was more of a sativa strain that initially sent my thoughts racing.