Patient Substance Abuse Characteristics.

<p>ASI, addiction severity index.</p>*<p>Variation in n due to variation in number of individuals responding to the ASI items.</p>1<p>The composite score ranges from 0 (no problems) to 1 (severe problems).</p>2<p>Percentage users out of valid responses.</p>3<p>Data expressed as mean (SD) of number of years in life that the drug has been abused (subjects who had not taken the given drug were excluded).</p>4<p>The ASI does not specify which drug was used intravenously.