1960s: Young American men are sent, often through the draft and against their will, to fight in the Vietnam War. Some seek to escape the horrors of guerrilla war by using illicit drugs like marijuana and heroin - the latter of which is cheap and readily available in Southeast Asia.

Today: Following terrorist attacks in New York and Washington, D.C., the United States engages in a war against terrorism, including military engagements in the Middle East. The terrorist attacks spark a patriotic response, and many young men and women choose to enlist in the armed forces.

1960s: The use of illicit drugs spreads into the mainstream United States. The counterculture movement of the 1960s and 1970s helps to promote this increased use of drugs, especially marijuana and LSD. Heroin, which is used by junkies (drug addicts), is often avoided by hippies.

Today: The heroin-related...