Heroin injection is the most prevalent registered cause of HIV transmission in Iran. Regarding the high prevalence of Intravenous heroin use among homelesses in Tehran; Iran Police force and Ministry of Health collaborated in a national project of capture and reference of these high risk group for opium detoxification using methadone maintenance therapy.we examined impulsive personality characteristics among captured homeless HIV positive or negative IHUs and compared them to their matched none captured, none homeless casually referred cases of intravenous heroi users (IHUs).

Two groups of HIV positive (25 cases) and HIV negative (25 cases) of Homeless IHUs had been compared to 50 cases of nonhomeless IHUs.we used Eysenk Impulsiveness Questionnaire-7 (EIQ), Barret Impulsiveness Scale-11 (BIS), and Delayed Discounting Task.Results:More prison history, criminal behaviors and longer history of needle sharing and drug abuse have been observed in homeless IHUs. More Impulsiveness indexes according to BIS, EIS and more delayed discounting had been observed in this group. And less venturesomeness measured by EIQ incentive. In the homeless IHUs who were HIV positive, more cognitive impulsivity detected according to EIQ and BIS tools.

Significant increase in impulsivity among homeless IHUs and lower life expectancy in addition to more needle sharing behavior in this group can be a clue for HIV transmission spread among this group. High degree of impulsivity alteration and longer history of addiction period, dose and frequency of needle sharing are among the other factors which may predict the risk of HIV spread amoung homeless IHUs.