It is reprinted here with their permission. The one piece of the definition that is slightly different regards the status of persons who illegally use drugs. The key issue is whether the use of the drug is illegal, not the nature of the drug or the way it was obtained. The legal use of a controlled substance under medical prescription is permitted. Moreover, there is a distinction made between the use of a controlled substance and addiction.
Addiction is considered a disability.
A person who is addicted to drugs but is not actively using drugs is considered a person with a disability and is protected by law. Alcohol is not considered a controlled substance. Section 504 has been changed to match the ADA regarding this exclusion of persons who are current illegal users of drugs. However, under Section 504, illegal users of drugs are still eligible for inclusion in health services provided by federally funded entities.