FRANÇAIS :
Les théories économiques nous montrent comment la montée du prix des drogues se répercute sur les consommations, de manière élastique ou non élastique. Dans l'étude présentée ici, réalisée sur 53 usagers, il existe un effet de substitution asymétrique entre l'alcool et la cocaïne chez les usagers abusant d'alcool. Lorsque le prix de l'alcool augmente, les ventes d'alcool et de cocaïne diminuent, mais lorsque le prix de la cocaïne augmente, la vente d'alcool augmente significativement. Les ventes d'autres drogues et de médicaments tels que le Valium ne sont pas affectées.

ENGLISH:
Economic concepts can be used. to assess how drug prices affect consumption patterns. Increases in price for a commodity typically result in reductions in consumption. Demand is considered elastic if decreases in consumption are proportionally greater than increases in price, and inelastic if they are proportionally smaller than rises in price. The price of one commodity can also affect consumption of others. Commodities can function as substitutes, complements or independents, and these concepts refer to increases, decreases, or no change in the consumption of one item as the price of another increases. This study evaluated the effects of drug prices on hypothetical drug-purchasing decisions in 53 alcohol abusers. Experiments 1, 2, and 3 examined how alcohol, cocaine, and Valium prices, respectively, influenced purchases of alcohol, cocaine, Valium, heroin, marijuana and nicotine. As price of alcohol rose in Experiment 1, alcohol purchases decreased and demand for alcohol was inelastic. Cocaine was a complement to alcohol, but other drugs purchases were independent of alcohol prices. In Experiment 2, demand for cocaine was elastic as its price increased. Alcohol was a substitute for cocaine, but other drug purchases did not change significantly. In Experiment 3, demand for Valium was elastic as its price rose, and all other drug purchases were independent of Valium prices. Hypothetical choices were reliable between and within subjects and associated with urinalysis results and lifetime histories of drug abuse. These results suggest that, among alcohol abusers, cocaine is a complement to alcohol, but alcohol is a substitute for cocaine. (Author's abstract.)