There is sufficient evidence that the spectacular AFP heroin drug busts of recent years has put a brake on the use of heroin and thus cocaine is becoming the drug of substitution. (More work for the AFP).
I think your chicken and egg comments are also a little foolish. In the case of prostitutes, particularly those who work in brothels, it is more likely that methamphetamines would be the choice of working drug for “working girls” (To keep them awake on the lonely night shifts or boring dayshifts). I don't think it would be hard to demonstrate that either by work or criminal activity addicts are supporting a habit. It's simply the power that an addiction has over its captive. Most addicts mix drugs, some of which are mind altering drugs, so to talk about using will power is an indication of an armchair approach and possibly indicates an abysmal ignorance of what chronic users suffer. There are many good programs to help addicts but the rule of thumb is that those who shoot up are beyond saving and almost always go back to their addiction.
The following abstract (and you can find ample supporting evidence) is an indication that drug abuse is affected by supply. This needs to be considered when discussing legalising the drug:
"The effect of a reduction in heroin supply on fatal and non-fatal drug overdoses in New South Wales, Australia
Louisa J Degenhardt, Elizabeth Conroy, Stuart Gilmour and Wayne D Hall
eMJA rapid online publication 15 November 2004
Abstract Objective: To examine the impact of a sudden and dramatic decrease in heroin availability, concomitant with increases in price and decreases in purity, on fatal and non-fatal drug overdoses in New South Wales, Australia.
Design and setting: Time-series analysis was conducted where possible on data on overdoses collected from NSW hospital emergency departments, the NSW Ambulance Service, and all suspected drug-related deaths referred to the NSW Coroner’s court.
Main outcome measures: The number of suspected drug-related deaths where heroin and other drugs were mentioned; ambulance calls to suspected opioid overdoses; and emergency department admissions for overdoses on heroin and other drugs.
Results: Both fatal and non-fatal heroin overdoses decreased significantly after heroin supply reduced; the reductions were greater among younger age groups than older age groups. There were no clear increases in non-fatal overdoses with cocaine, methamphetamines or benzodiazepines recorded at hospital emergency departments after the reduction in heroin supply. Data on drug-related deaths suggested that heroin use was the predominant driver of drug-related deaths in NSW, and that when heroin supply was reduced overdose deaths were more likely to involve a wider combination of drugs.
Conclusion: A reduction in heroin supply reduced heroin-related deaths, and did not result in a concomitant increase, to the same degree, in deaths relating to other drugs. Younger people were more affected by the reduction in supply.
