I'm a bit confused, because I was under the impression that allergy meds containing ephedrine were banned a few years back. I guess you can still get them somehow. Basically, ephedrine is a stimulant found in the herb ephedra, or ma huang in Chinese. It has been used for centuries as a decongestant, and some use it as a stimulant. Because both ephedrine and its cousin pseudo-ephedrine can be used to make methamphetamine, regulators basically banned the stuff. I think this was a mistake, and asthma sufferers were particularly affected -- the basic herb has very little of this in it. What you're taking has a lot, so you're basically taking speed. Speed is actually commonly used for depression, but when you get it from a psychiatrist, the dose is controlled. When you do it yourself the way you're doing it, yeah, you can become habituated to it and possibly addicted, though ephedrine isn't as addictive as amphetamines. But it's the same idea. This is why some antidepressants are very stimulating, so much so they can cause anxiety, as can what you're doing. The snri category and wellbutrin, for example, are stimulating antidepressants. Taking more and more as you're doing is an obvious sign of abuse, which I guess you know or you wouldn't have posted on here. Speed is also used for ADHD sufferers, for better or worse, though with them they use the harder stuff, amphetamines.