October 18, 2016
Many societies more or less rigorously enforce their prohibition laws with respect to cannabis products (e.g., Hashish, Marijuana) and physiologically more addictive drugs (e.g., Cocaine, Heroin). To justify cannabis prohibition, it is often argued that its enforcement reduces the consumption of hard drugs. Using standard assumptions of prohibition advocates, this paper examines the validity of this argument. Specifically, it models the entry into drug consumption by combining the economic model of crime with some empirical findings from drug research. Assuming a sequential entry into the consumption of light and hard drugs, a formal analysis shows that a more rigorous enforcement of cannabis prohibition may rise the consumption of physiologically more addictive drugs. It further shows that an insufficiently differentiated punishment of the consumption of more and less addictive substances may increase the number of hard drug consumers. The analysis thus indicates inconsistencies in the standard argumentation in favor of cannabis prohibition.