Objective: This study aimed to compare two groups of substance abusers and healthy people with each other in individual risk factors and to identify the most important individual risk factor that draws a distinction between the two groups. Method: A retrospective method was used in this study. Indeed, 120 substance abusers and 120 healthy subjects who were matched with each other in demographic characteristics. These particpants reosnded to the items of anxiety, stress and depression, impulsivity, aggression, attitude to substance, and status of substance use. Results: The results of this study showed that the patients with substance abuse obtained higher scores in individual risk factors in comparison with the control group. Impulsivity, aggression, depression, and positive attitude to drugs were respectively the most discriminant factors in distinguishing the two groups. Conclusion: The results show that internal defects in substance users make them susceptible to abuse drugs. Negative emotions, positive attitude to drugs, and the inability to control impulses lead them to use the variety of substances.