E was accidently created by someone who was tring to make crystal meth but screwed up on the compounds. It eats holes in your brain - same as meth. It is speed off by one molecule. You can read it's history on the internet.
It may not have the same intense "craving" component as meth but it completely depletes your serotonin levels and leaves you depressed afterwards, which leaves you wanting something to make you feel better and whole again. Another hit of E. A line. A puff. A drink. Anything to change the way you feel.
A drug is a drug is a drug. One leads to another. Stellargirl is right. Don't waste your life dating drug addicts. I did. I wish I would have found a whole person when I was younger. Not one who needed drugs to feel complete.