Due to its progressive nature in all aspects of life, addiction endangers the health of individuals, families and the society. Substance abuse (e.g. stimulants and psychotropic substances) has increased in recent years in Iran due to a lack of cultural and social considerations as well as inefficiency of prevention programs (
1). A prevalence of 800,000 to 2.5 million addicts, four times increase in the number of addicts of drug rehabilitation centers during 1983 to 1996 and 3 to 6 % incidence of addiction in Iran verify this claim. On the other hand, 90% relapse of addiction after quitting in Iran indicates that many more attempts must be made for understanding the causes of propensity to this predicament and identifying effective ways to deal with it (
2). One of the important factors affecting substance abuse is interpersonal reactivity. People who cannot control their excitements are possibly more at risk of substance abuse (
3). Excitement and impulsiveness are personality characteristics of those who demonstrate high reactivity toward life events. These are among the factors that affect problematic behaviors, especially substance abuse. Chassin et al. and Blackson et al. found that emotional reactivity is associated with early drug abuse. They concluded that emotional reactivity is a risk factor for starting substance abuse in the future (
4,
5). In a research, Fox et al. found that drug abusers have many difficulties in regulating, understanding and managing emotions and in controlling impulsivity, especially at early stages of tendency to drug (
6). One of the factors affecting the interpersonal reactivity of addicts is self- regulation. Some researchers argue that self- regulation (
7) and interpersonal reactivity (
3) can be influenced by drugs. Self-regulation requires controlling of conscious efforts and the ability to act on self-guided arrangements away from any internal reward and support. This is essential for recognition, monitoring and changes of behaviors versus environmental changes (
8). Self-regulation is considered as mental efforts in monitoring internal conditions, processes and functions in order to achieve higher goals (
9). In a research, Glassman et al. showed that self-regulation strategies are the best predictor of alcohol consumption, such that self-regulation refrains people from alcohol consumption (
10). In their research, Doran et al. found that those who have low self-regulation have less ability to predict others’ needs and are often drawn towards smoking (
3). In a research on 787 drug addicts, Cole et al. concluded that emotion, cognition and behavior derived from low self-regulation, could predict substance abuse disorders (
9). Due to their family history, these people are more at risk of substance abuse. Therefore, failure in self-regulation plays an important role in relapse of drug abuse. In their research, Abolghasemi et al. concluded that drug abusers with high reactivity bring into play more negative emotion regulation strategies (
11). Another variable that can influence the interpersonal reactivity of addicts is affective control. Studies have shown that inadequate emotional growth, difficulty in organizing behavior and having negative excitements are among the characteristics of drug-prone people (
12). Copeland et al. showed that 71% of methamphetamine abusers received diagnosis of mood disorders, and 27% received diagnosis of anxiety disorders (
13). Pitts et al. found that the effects of stimulants on self-control behaviors may be due to a reduced sensitivity of behavioral reinforcements (
14). Vik showed that there is a positive relationship between methamphetamine abuse and psychiatric disorders (
15). In a study, Parker et al. found that the failure to establish an emotional relationship with others results in drug abuse (
16). Research evidence have indicated that use of methamphetamine is associated with depression (
17), antisocial behaviors and depression (
18), psychosis damages and anxiety (
19) and low self-control and depression (
20). The research results of Cole et al. also showed that self-control and personal control have a negative relationship with received stress in drug abuse (
9). Given that the role of these variables are not appropriately highlighted and due to excessive tendency of the younger generation towards stimulant drugs as well as the importance of self-regulation and affective control in this age group and considering research gaps in this area, conducting this study is important and necessary. The aim of this study was to determine the role of self-regulation and affective control in predicting interpersonal reactivity of drug and psychotropic drug addicts.