Substance dependency is a deviation that in many years exposed the humankind mainly youth, to the risk situation. In the recent years, young people are the main victims of this phenomenon. Regarding to character of our society that youth are majority of population and because this group is targeted in preventive programs of substances, so this research was done to describe the experiences of youth with substance dependency about causes of substance use.

This is a qualitative- phenomenological study. Participants in this study were 12 youth with substance dependency with range of 18 to 30 years old that was selected with purposive sampling method. Data were collected with in-depth interview and analysis was done via Colaizzi method.

Three themes or main concepts were derived from this study that each of these themes has any subthems. These are including Personal factors, Family factors and Social factors.

The findings of this study indicated that people underlined of different factors such as personal, family and social factors refer to the consumption of opioid and finally depend to this substance. Regarding to findings of present study, the researchers of this study believed that the first level of prevention can useful about this. Thus in this level of prevention, three approaches of individual centered, family centered and community centered suggested.