Drug use is part of American culture. Hundreds of drug products are available for personal use at any local pharmacy. Millions of people use a stimulant every morning when they drink a cup of coffee. Many Americans consume alcoholic beverages, not only at parties and bars but also at formal celebrations such as weddings, and alcohol is often used symbolically by Christians and Jews.

Unfortunately, drug abuse is also part of American culture. Differentiating between drug use and drug abuse is not always easy, and a variety of criteria are often used to determine if a person is using or abusing drugs.

For many people, medical need is the key determinant in deciding whether a drug is being abused. In this view, the only legitimate use of drugs is for improving one’s health or wellbeing; the use of...