Patients who use drugs intravenously may be at high risk for relapse, but their situation is no more futile than that of persons with diabetes and coronary artery disease who smoke and frequent all-you-can-eat buffets.
Advance directives, substituted judgment, and the best-interest standard all have limitations that constrain their usefulness in making medical decisions for patients who cannot choose for themselves.
The practice of banking sperm from adolescents about to undergo chemotherapy is not universal, which lends support to the argument that parental consent be required for the intervention.