speed is plain pure amphetimine (sp) crystal meth is sim. in structure but not in effects on body, meth is much more addictive and harmful for you can cause you to pick at your skin and altogether can practically destroy your life. there are many things related to speed , coke is called something like cocamphetimine sim. in structure but slightly different ain smae family, and crack is coke freebased which causes a different reaction to you cause it goes through a chemical reaction (combustion) makes it more addictive and such, ridilin, concerta is methylphenidate, also sim. in structure but still differnt effects, and there are others all in the same family all do essentially the same things but have variations of effect and how much you enjoy it all quicken your heart rate and may make you feel sped up. speed can be reffered to pure basic amphetemine (but its still often cut with shit cause dealers wanna make lots of profit) but it can also be used as a general term for anything in the amphetimine family of chems, your friend is probably not talking about coke or meth or he will use the terms coke/blow, meth/gib and or other slang terms. sp he would be refferring to speed but ti will be cut with other shit, not referring to other drugs although maybe but he could be inclusding like baking powder or drywall or some dumb thing such as, or it could be cut with ice, crystal, meth, gib whatver you wanna refer to it as because that stuff is more addictyive and willl get people hooked fasater