@article{ref1,
title="Drug abuse and mental illness: progress in understanding comorbidity",
journal="American journal of psychiatry",
year="2001",
author="Volkow, N. D.",
volume="158",
number="8",
pages="1181-1183",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0002-953X",
doi="10.1176/appi.ajp.158.8.1181",
url="http://dx.doi.org/10.1176/appi.ajp.158.8.1181"
}