I suspect that a drug intended to make time go more slowly is the last thing Sherlock would take, given how many of his problems come from the perceived meaningless of existence and general ennui. That said, I've been worried for some time that he's going to relapse, but I'm hoping that his speech about a relapse being an anticlimax is a message from the show runners that the story of a man who manages to maintain his sobriety is more fulfilling in the long run than the story of a man who tries and fails. Which is both something I can absolutely get behind as a viewer, and also a good message to put out there for people who are struggling with addiction.

(One thing that I like about this show is that they seem to be aware of the consequences of what they put into the world, and committed to showing emotionally healthy people behaving in emotionally healthy ways and having good relationships as a result. It's refreshing, actually.)