An official website of the United States government
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.
Karschner EL, Schwilke EW, Lowe RH, Darwin WD, Pope HG, Herning R, Cadet JL, Huestis MA.Karschner EL, et al. Among authors: schwilke ew.Addiction. 2009 Dec;104(12):2041-8. doi: 10.1111/j.1360-0443.2009.02705.x. Epub 2009 Oct 5.Addiction. 2009.PMID: 19804462Free PMC article.