Mainly that prohibition creates and supplements addictive behavior; by associating conditions created by prohibition (the 'dirty' or dangerous aspects of illegal drug use) with the effect of the drug of choice, it reinforces that addictive behavior in its most dangerous and harmful guises. Ex. areas of run down urban areas become drug open air markets, people who use associate run down urban areas with being high, it was found that being excited about the setting a user is going to get high in has an impact on the effect of the high (i.e. getting an injection by a nurse of heroin in a maintenance clinic in Switzerland vs injecting in a filthy alley behind a run down building), due to neurotransmitter release (dopamine, seratonin, norepinepherine)- which reinforces that dangerous behavior. But there's a ton of stuff they've studied and written about.
"If you're interested in those aspects of prohibition and drug policy, I'd recommend reading the Harm Reduction journal (I think it's part of the Addiction Sciences journal series out of the UK if memory serves). They've done a lot of dynamic research on the effects of prohibition on demand and the creation of sub-cultures around particularly dangerous demand side activities." Would you mind telling me what their conclusions were?
