Mosayeb Yarmohamadi Vasel - Department of Psychology, Buali Sina University, Hamadan, Iran.
Mahmoud Tavakoli - Substance Abuse and Dependency Research Center, University of Social Welfare & Rehabilitation Sciences, Tehran, Iran.
Fatemeh Ghanadi - Department of Psychology, Kharazmi University,Tehran, Iran.
Ali Farhoudian - Substance Abuse and Dependence Research Centre, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
Mohamad hasan Farhadi - Substance Abuse and Dependence Research Centre, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.

Objectives: Drug injection carries with it many risks and therefore it is important to understand the initiating factors of injection and its origins. Thus,  the purpose of this study was to identify factors associated with the initiation of injection drug use among substance abusers. Methods:  Study method was a cross-sectional study. The research statistics universe constitutes all people suffering from a substance dependence disorder with a pattern of injection use in Tehran and Hamedan. This study was conducted among ۲۱۶ individuals with substance dependence disorders who were selected from harm reduction centers in Tehran and Hamedan. The sampling selection method was simply random. The instruments used for data collection included: demographic information, patterns of drug use and initiation of injection scales.  Results: In this study, the average age of initiation to injections was ۲۲.۵ years. Factors associated with initiation of drug injection included: acquired more pleasure, easier use, faster effect of injection, ineffective previous use method, curiosity, peer pressure, lack of availability of the drug, poverty, and low quality drugs. Discussion: Results of this study indicate that initiation factors to drug injection are multifaceted (Psychological, Social, Economic and Environmental), therefore, injection interventionists should consider all these factors for prevention, treatment and harm reduction.

Addiction, Transition, Injection pattern, Initiation of injection