physical and psychological consequences of its abuse. Marijuana, along with LSD and heroin, was placed in Schedule I, the most restrictive category. Schedule I substances are considered to have no medical use and a high potential for abuse.
That classification continues to be challenged by the National Organization for the Reform of Marijuana Laws and medical marijuana advocates. In addition, since passage of the federal Controlled Substances Act, several states have placed marijuana in a less restrictive category in their own controlled substance laws. In the 1970s and 1980s several states even supported limited clinical studies on medical marijuana. Voters in several states have passed referenda intended to permit marijuana use for medical purposes (see Chapter 11).
Despite its illegality, millions of Americans use marijuana regularly. A small minority—most of whom had previously used the drug recreationally —smoke or eat it to relieve various medical symptoms. In three public hearings held by the IOM as part of its study of medical marijuana, 43 such patients came forward to relate their experiences (see Figure 2.4); the research team also