Ftr, misuse (due to lack of maturity, usually, I would say) of anything can lead to addiction (or trouble sleeping, for that matter). Ephedrine does not cause physical dependence. Caffeine does, though.
Most people recommend not taking the stuff (ephedrine) anywhere later than early-mid afternoon so as not to disrupt sleep (sadly, ephedrine is not tolerated like caffeine is [hence the physical "addiction"] - not the parts that would keep you awake, that is), but me, I find it doesn't matter what I've taken when my body decides it wants to sleep. It's actually a bit of a problem, really. I am pretty well immune to wake-me-ups. And alarm clocks. Even the kind with fists.
I once drank 18 Red Bulls and nearly 3 litres of Grey Goose and then decided to go to sleep (no, that's not a euphemism for passed out, and I was actually sitting upright in a chair
) and slept the sleep of the just. This in spite of the fact that both alcohol and caffeine (which I was not tolerant to at the time) are supposed to be disruptive to sleep, let alone able to kill someone in that quantity.
While doing so makes me a very stupid person (and I most certainly was, seriously, kids don't try this at home - people die from less willful idiocy than that all the time), I mention this to illustrate the fact that when it comes to health and fitness a lot of what happens is a personal thing. In cases where it's a question of "possible side-effects include...", it's all down to the individual. With ephedrine, it's a 'you might maybe hurt yourself if you're really unlucky and dumb about it'. Which is why I don't see the difference between it and say... every "legalized" drug sold in North America. Smoking cigarettes, for example, will definitely wreck your ****, but they're okay because the government makes a killing off of them!