Spoiler: it's not drugs, you have to watch it till the end, and I mean it, really until the final season. I can't say much more than this without spoiling the very heart of the show.

In the final season, Mr. Robot does some fairly ambitious episodes. One of them is a continuous tracking shot (or made to appear as one) that goes through the entire episode. Another one has no spoken dialogue for the majority of the episode. A very well-written show. And yes, you really do need to see it all the way through.