Question 1: When was opioid addiction first observed in the United States?

Answer: Widespread prevalence of opioid addiction was first documented in the United States following the U.S. Civil War of 1861-1865, when narcotics administered to injured soldiers prompted observers to describe addiction as "the Army disease" (Hentoff, 1965).

References

Hentoff N. The treatment of patients - I. The New Yorker 1965;June 26:32-77.