Extended Abstract
1. Introduction
The purpose of this study was to determine the role of impulsivity, rewarding sensitivity and anhedonia between individuals with borderline personality disorder and normal people. According to the theory of reward deficiency syndrome, although impulsive behaviors are quite associated with possible injury or loss, yet they provide the conditions for achieving a type of reward. The reward deficiency syndrome is a psychological theory first noticed by Blum, which is known by the search for reward-seeking behavior or addictions. According to Blum’s research, people with reward deficiency syndrome tend to follow the most severe emotions, since it allows them to feel continuous and permanent enjoyment and reward, thereby the dopamine levels increases in their brains. Reward sensitivity, in disorders associated with reward deficiency syndrome, means that individuals do not enjoy the usual rewards seeking process in their natural and daily life activities which leads to various mental disorders, abnormal and resistant patterns of achieving rewards and pleasure.
2. Method 
The research method was descriptive-correlational. The statistical population of the present study included the students of Tabriz University in the 2016-17 academic year. According to the research method, 200 people in the first stage were selected by screening, and according to the Tabakhnick & Fidell formula, 80 were selected by purposeful sampling in the second stage. In fact, according to the mean and standard deviation obtained on the Millon scale-3, 40 people with borderline personality disorder and 40 normal people were selected. In other words, the subjects’ scores were converted to the standard Z score, those who had a score of above Z 1.5 were considered as individuals with borderline personality signs and those with a low Z-negative of 1.5 were normal individuals. In other words, the conversion of raw scores to Z scores standardized and displayed the scores of subjects in Z’s distribution with mean as zero and standard deviation of one in turn controlling the scattering. To measure the variables in the first stage of the study, the Millon-3 questionnaire was used to screen individuals with borderline personality disorder, computerized task of balloon risk for measuring the impulsivity variable and the Essen and Hamilton’s pleasure scale for measuring anhedonia variable. 
3. Results
The results of the study showed that the impulsivity variable with the coefficient of 0.61 has the most effective role in the discriminant function while the sensitivity of reward variable with a coefficient of 0.47 and the anhedonia variable with a coefficient of -0.42 are second and third in order, respectively. 
4. Discussion
In sum, the results of present study indicate that impulsivity, rewarding sensitivity and anhedonia are the most important factors in differentiating between the individuals with borderline personality disorder and the normal individuals. According to the theory of reward deficiency syndrome, Eysenck’s, Gary’s, and Zuckerman’s, it can be said that these three characteristics have a high diagnostic value in individuals with borderline personality traits. As per Eysenck’s theory, people with higher emotional instability (such as borderline personality) are more sensitive to threats and reward signs/clues, thus because of anhedonia, they look for excitement and incitation in the environment. According to Gary’s theory, people with high impulsivity have a higher sensitivity in the BAS system which makes them more capable/susceptible to potential rewards symptoms and have a low inhibitory mechanism, seen in addictive and enthusiastic behaviors. On the other hand, according to Zuckerman’s theory, seekers of superior senses are in a state of anhedonia, therefore need more powerful stimuli to achieve optimal levels of arousal. He also stated that while facing with challenging and reward-based task, responses are more severe. 
Thus, according to the theory of reward deficiency syndrome, a defect in the brain reward system is a kind of deprivation of sensory mechanisms in individuals with signs of borderline personality. This leads to anhedonia, low arousal and finally leads to impulsivity in such individuals. However, more studies are needed to clarify the role of the reward deficiency syndrome in borderline personality disorder. In general, the results of the present study can be inferred that anhedonia can be considered as an underlying factor in the incidence of impulsive behaviors and abnormal patterns of reward seeking in people with borderline personality signs. However, the clarification of this issue requires further researches.
Ethical Considerations
Compliance with ethical guideline
The participants signed the informed consent form and had the right to leave the study at any time.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The paper was extracted from the last author MA thesis in the Department of Psychology, Faculty of Education and Psychology, Tabriz University.
Conflict of interest
There authors declare that they have no conflict of interest.
Acknowledgements
In the end, we thank all the participants who helped us complete this study.

 

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