Another study, published in 1993 in the American Journal of Psychiatry, found that 18 percent of intravenous-dug abusers diagnosed with antisocial personality disorder were HIV-positive, while only 8 percent of intravenous-drug abusers without antisocial personality disorder tested positive for HIV. The higher odds ratio of HIV infection among sociopaths is presumably due to their greater risk-taking behaviors.
--Martha South, Ph.D. in The Sociopath Next Door, p187.