benefits of administering an effective antismoking treatment to a long-term smoker would be in the range of thousands of dollars per patient. The amount would be substantially higher for a chronic alcoholic and higher still—in the tens of thousands of dollars—for someone addicted to heroin or cocaine.
It is hard to imagine that the financial costs of making an immunotherapy agent, administering it to a patient, and doing the necessary follow-up could even approach such levels. Current estimates are that the treatments will cost on the order of a thousand dollars per administration and that each administration will be efficacious for a few months. So if a highly efficacious, low-side-effect immunotherapy were developed for any of the major drugs of abuse, its application to anyone with an established chronic problem with that drug would almost certainly be cost-justified.
If the efficacy were only partial, if side effects were substantial, or if substitution of other drugs turned out to be a major problem, the calculation would become more challenging. An immunotherapy that prevented three-quarters of an abusable drug from getting to the brain might have much less than three-quarters of the benefits of a completely effective immunotherapy, or it might have virtually the same benefits, depending on behavioral responses that as yet can only be guessed at. (Partial interception would be equivalent in some ways to a price increase, and the behavioral response would reflect an analog of the price elasticity of demand. The more elastic [sensitive] consumption of a drug is to its price, the greater the benefit of a partially effective immunotherapy.)
Use in patients with less chronic conditions, or prophylactically in those without established drug problems but engaged in drug-taking patterns that threaten to escalate, would be less beneficial per case but might still be cost-justified in some instances (National Research Council, 2001).
The second kind of cost-benefit question that might be raised involves expenditures on the development of such therapies. That development analysis uses the patient-by-patient analysis as its starting point, but the relevant part of the patient-by-patient analysis is not the part that deals with the interesting close questions such as the possibility of prophylactic use or use in cases of a relatively mild abuse disorder or a disorder not yet shown to be chronic. Instead it is the benefits in the cases that are most obvious in the patient-by-patient analysis—patients with severe, chronic disorders—that need to be summed and then measured against the costs of a development effort and its probability of success. This appendix will pass over the questionable cases to concentrate on the clear ones. (It would be somewhat perverse to oppose the development of a medication on the grounds that, if developed, it might then be used badly in some instances, though far from perverse to try to anticipate and forestall such usages.)