well if u want to get technical, cocaine is a scheduled II drug, meaning it's slightly less addictive than the other two (which are schedule I), however heroin is used as a analgesic in other countries, but in the US i've been told that hospitals still sometimes use it as a topical analgesic prior to a major surgery. since it's a opioid, it's structure is actually fairly similar to morphine and other painkillers. basically it's a pharmaceutical agent that has been abused to the point where it is now illegal
meth, hmmm well there are many ADD/ADHD medications on the market that are derivatives of amphetamines, ritalin being the most popular of these. i personally think the whole class is useless, but hey, whatever floats your boat i suppose
the main dangers of these products don't come from the actual substance itself, because in pharmaceutical grade, quality products, they will not have much of the dangers as street products. much of the dangers come from either mistakes in the process of developing the drugs, or in cutting the drug with other chemicals so that you don't get a pure drug
as to which is most dangerous, i'd say meth, just because the meth labs themselves are pretty dangerous from what i've heard, and i think putting others in risk just to get a high makes it more lethal than any of the others
aaand i'm done now :3 *runs off*
