An official website of the United States government
Here’s how you know
The .gov means it’s official.Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.
The site is secure.The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.
Creswell, Kasey G.; Terry-McElrath, Yvonne M.; Patrick, Megan E.
Drug and Alcohol Dependence