Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Drug use history and most preferred substance
α “Any opioid” is a composite variable representing combined responses to heroin, and any other opioid-based substance. It should not be included in the sum of the percentages of most preferred substances.
