A B S T R A C T

Introduction: Although decision-making processes have become a principal target of study among addiction researchers, few researches are published according to effects of different treatment methods on the cognitive processes underlying decision making up to now. Utilizing cognitive modeling method, in this paper we examine the effects of Methadone maintenance treatment (MMT) on cognitive processes underlying decision-making disorders in heroin-abusers.

 Methods: For this purpose, for the first time, we use the balloon analog risk task (BART) to assess the decision-making ability of heroin-abusers before and after treatment and compare it to the non heroin-dependent subjects.

 Results: Results demonstrate that heroin-abusers show more risky behavior than other groups. But, there is no difference between the performance of heroin-abusers after 6 months of MMT and control group. Modeling subjects’ behavior in BART reveals that poor performance in heroin-abusers is due to reward-dependency and insensitivity to evaluation.

 Discussion: Results show that 6 months of MMT decreases reward-dependency and increases sensitivity to evaluation.

A B S T R A C T

 Abstract- Methamphetamine has rapidly become more prominent in Iran, which is now second most common drug behind heroin. Moreover, initiation of methamphetamine abuse is a major cause of failure of opioid treatment programs such as Methadone maintenance treatment. This calls for development of more effective treatment methods for methamphetamine addiction, and especially development of techniques for evaluating of their effectiveness in a laboratory and controlled settings. Measuring the reinforcing efficacy of a drug during the course of a treatment can provide such an evaluation, which is typically based on self-administration procedures. This article is aimed to summarize and discuss self-administration procedures that are commonly used in human research, and especially the particular value of these procedures in studying methamphetamine addiction. We also present a self-administration procedure for assessment of reinforcing efficacy of methamphetamine.