Check recent logs from Wilsmith. Wil no longer can afford extensive training however he still wants to stay competitive. Long story short - he plans to switch to interval training 3 about times per week, less then hour per session. It's practice that middle distance runners do to maintain their shape. If your training is spotty - it might be training method that would work better for you then occasional LSD.
I can assure you that I have many bad habits but taking LSD is not one of them:)
Seriously though, I think I need to build same anaerobic base before starting to do intervals (though that might be just another way of saying that I am too lazy to do them). Since I amm remotely aiming to do the London Marathon in spring, I hope that my training will become more regular - when I was training for the NYC Marathon, that was a pretty good motivation.
LSD stands for "Long Slow Distance".
However speaking of additions: runners do get so called "runner's high" when running at their top capacity. It's painful and adictive at the same time.
Yes, I did realize that you were not advising to take psychotropic substances and while running I managed to figure out what LSD stood for.