My opinions on the matter are similar to those of maduin although permit me a tweak on them. I will agree it is a matter of perception though.
For a start have you been to many medicine cabinets or turned on the TV recently I see
sleep both getting some and waking from medicated.
I see the digestive system medicated in every way possible.
I see all types of waking mental state able to be changed.
You have caffeine used by millions.
You have alcohol used by about as many.
You have tobacco (a drug of little medical benefit although there is some) used by millions.
If you want to take it a step further how many times have you necked a bunch of sugary foods for the "instant pick me up". Synthetic sugars are not easy chemistry.
A bit of searching is sure to give examples of how (ab)use of these has the ability to mess you up.
History also plays a part which maudin touched upon and I see no reason to expand upon right now.
I will say maduin's point about the legal drugs (as in pharmaceuticals and not the alterations on existing drugs to make them legal) is a bit narrow minded in that there are not too many classes of drugs*, my knowledge of pharmacology is not all that it could be so we are going to run into a wall with regards to what I know but I can tell you small changes on complex organic compounds (which most drugs are) can have profound effects, hell even geometric isomerism: same chemical makeup and bonds but some bonds are spun around on an axis: http://usm.maine.edu/~newton/Chy251_253/Le...ricIsomers.html
affects things, the most pertinent example is probably thalidomide: http://www.chromatography-online.org/topics/thalidomide.html
which when the right version is used is safe for babies.
*a the risk of a broad generalisation and my invoking
psychology most drugs act on neurotransmitters (you will probably have heard of serotonin, dopamine and possibly gaba), you may want to ask why glutamate is only just starting to be investigated (for what it is worth PCP affects this). The risk is high but so is the potential reward, this lack of desire to experiment is one of the reasons I am not a great fan of psychology as it presently exists.
I would certainly never say there are no negative effects of drugs but those you describe are as maduin mentioned suffered by those with lack of control; heroin is often used as an example of a terrifically addictive drug but when you look at the stats from Vietnam (a stressful time for all concerned if you ask me) which had high usage rates by anyones estimate yet most repeat uses do not seem that high ( http://www.ingentaconnect.com/content/bsc/...taar9.alexandra
), granted injection versus other methods of taking it come into play.
Just to wind it into another point you mention violent games, as the media is often quick to tell us some of the less desirable elements of our society have played games that could be considered violent at some point. Is this a game causing or someone predisposed to things being drawn to a game. Alcoholism has been documented to run in families (no sources right no other than http://pubs.niaaa.nih.gov/publications/Fam...ory/famhist.htm
but I am sure I can dig one up), is it such a stretch to say the ability to go off the rails is also applicable to "hard drugs".
Also meth (speed) is not so popular in Europe but most of the methods used to cook it up (see bathtub meth) are what does the damage. That is not to say it lacks the ability to mess you up but it is not a binary state of affairs.
You mentioned marijuana, not to start on that route but I will say the statistics speak for themselves with regards to how many people truly suffered from it. Compare it to something like alcohol and then tell me it is worse. Also it is legal in parts of the world; how does that fit in.
Secondly the legality of things is also debatable; see for instance the recent UK dowgrading and subsequent upgrading of cannabis and how the scientific community decried the lack of science used in the debate (the opinions of the experts consulted were ignored: http://www.theregister.co.uk/2008/11/25/ca...s_lords_debate/
). Should logic trump law; consider some muslim countries where women are kept covered where there is no logical reason to. Presuming I word it properly but still voice disapproval I am sure to encounter and element of "it is there country and they can do as they please".
Next up is age at which things are "legal", this varies over the world but more importantly age comes with an assumed physical state (the effect of alcohol is linked to body mass amongst other things).
One further point and just to round off the perception thing: when you see people running around going "whooooo" at a party consider that it takes a bit longer than you might think for alcohol (especially what passes for beer stateside) to take effect.
Finally when debating general stuff your own experiences are of little use as they rarely represent the general state of things. For example there were 4 adults in the room last night and 3 of us had a considerable level of knowledge of electronics; obviously 75% of the world do not have that.
And just to go against my own point my only method of mind expansion is sleep deprivation, the only medicine I have used has been a decongestant and antibiotics as and when they are needed. I have no objection to people doing anything either as long as it does not adversely affect others.