"Note here a similarity between needle-sharing and unsafe sex: at the point of risk--shooting up and orgasmic exchange of bodily fluids--the "decision maker" is least likely to be "processing" information in a rational cost-benefit way. Again, Aristotle might be right to suggest that at certain moments we take leave of reason and throw ourselves into craving and compulsion. Choices to shoot up or to go for a risky orgasm under these circumstances can be understood as made under diminished capacity--momentary choices that cannot be considered utility-maximizing. Interestingly, the two phenomena, drugs and sex, sometimes combine in a synergism of risk. Studies suggest that partners are more likely to engage in HIV-risky sexual activities when they have been using drugs. 34 By clouding the mind or releasing inhibitions, drugs can induce an acquiescent or skewed judgment yielding a momentary utility calculation not reflective of one's ordinary thinking. We are reluctant to consider such scenarios as utility-maximizing for both participants."
-- William Eskridge, "The Economics Epidemic in an AIDS Perspective," 61 U. Chi. L. Rev. 733, 750 (Spring, 1994)