Background and objectives: Establishing centers to stop addiction in our country is one of the measures taken to confront this problem. Unfortunately, it has been shown that about 80% of the addicted people who refer to these centers relapse. The present study set out to investigate the possible causes of this problem.

  Methods: This is a case control study in which a questionnaire was used to collect the required data. The subjects were all addicted people who referred to Shahid Mellat Doust and Shahid Family treatment centers in 2000. The criterions for entering the study in case group were the last record of the addicted person ’ s abandonment in Tehran ’ s welfare center ( based on the patients ’ records) and using narcotics at the present time. The control group subjects, on the other hand, had abandoned using narcotics at least four months before and had never used any substance so far.

  Results: The mean age for case group was 35.99 and that of the control group was 35.09. Regarding the age distribution 98.59% of the case group and 100% of the control group were men. 88.7% of the case group and 97.2% of the control group were urban residents. Considering the job, 40.8% of the case group and 19.4% of the control group were unemployed. 52.1% of the case group and 61.6% of control group were living with their spouses. Opium was the most commoly used narcotics in both groups. In studying the relationship between the variables under study through logistic regression the job was not a main factor in the relapse. The duration of time being away from addiction had a deductive effect on the relapse, and this effect was statistically meaningful (p=0.001). Adding one month ’ s time to the period of being clear (not using the narcotics) caused 98% deduction in returning to narcotics.

  Conclusion: Because 80% of the patients who referred to the related centers began using narcotics again during the first 6 months after abandoning, it is necessary to improve the preventive measures to help the patients pass this critical period.