"Contrary to conventional wisdom and popular myth, alcohol is more tightly linked with more violent crimes than crack, cocaine, heroin or any other illegal drug. In state prisons, 21 percent of inmates in prison for violent crimes were under the influence of alcohol--and no other substance--when they committed their crime; in contrast, at the time of their crimes, only three percent of violent offenders were under the influence of cocaine or crack alone, only one percent under the influence of heroin alone."

Source

Califano, Joseph, Behind Bars: Substance Abuse and America's Prison Population, Forward by Joseph Califano, The National Center on Addiction and Substance Abuse at Columbia University (1998).
http://www.casacolumbia.org/a…