Extended Abstract
1. Introduction
Gaining reward and pleasure is one of the major factors among individuals with depression, the lack of which leads to issues with respect to the affective levels in depressed individuals, and consequently, the defect in earning rewards, would lead to decreased activity and social reinforcement and increased negative thoughts, affective level, and motivation. This phenomenon would form a vicious cycle that would lead to the continuation of the depression disorder. Also, since rewards are essential for betterment, they are desirable and sought after. Therefore, using rewards creates enjoyable effects, and this factor leads to consolidation of a tendency towards using rewards. Yet the depressed individuals, because of deprivation of sensory mechanisms of pleasure in brain, cannot enjoy normal rewards and daily activities. On the other hand, based on the behavioral theory, depression is a chain of loss, decrease, lack of reward, and inability to earn rewards in interpersonal relationships. Therefore, the present study was aimed at investigating the effect of reward-based tasks on affective levels in depressed individuals. 
2. Method
The present study used an interventional method and the cohort comprised of students of Tabriz University in the academic year of 2016-2017. The sample size included 40 students, who had referred to the University counseling center, were divided into two groups of control and intervention (n=20 per group) through random assignment method. The intervention was given to the experimental group during 8 sessions (45 minutes per session) and 25 days by the Balloon Analogue Risk (reward-based task test), and the equivalent score obtained in each session was given to material rewards. For data assimilation, the Beck Depression Inventory (BDI) and Mood Adjective Check List (MACL) were used. 
3. Results
The posttest mean scores of participants based on the reward-based task in the intervention group were 18.1, 12.6, and 14.1 for hedonic tone, tense arousal, and energetic arousal, respectively, and 13.9, 19.3, and 13.2, respectively for the control group with significant differences (P=0.01). The effect size of the present intervention was 0.70. In addition, the observed difference between the mean scores of the affective levels in the participants based on the reward-based task in the intervention group (by mean scores of 15.7, 14.4, and 11.7 for hedonic tone, tense arousal, and energetic arousal, respectively) and the control group (by mean scores of 14.1, 18.9, and 13.6 for hedonic tone, tense arousal, and energetic arousal, respectively) was significant in the follow-up stage (P<0.01). The provision of the reward-based task had been effective in improving the affective levels of participants in the intervention group in posttest and follow-up stages, and a statistical power equaling 1.0 indicated a reliable statistical accuracy. 
4. Discussion 
Assigning the reward-based task to individuals with depression symptoms led to an increase in hedonic tone. According to Frester’s model, depression consists of a chain of loss, reduction or lack of reward, and inability to gaining rewards. Thus, depression is the cause of failure to achieve reinforcers, and until this vicious circle continues, depression would stay stable; therefore, depressed individuals can be aided via improvement of their affective levels by offering rewards. In addition, offering the reward-based task to individuals with depression disorder symptoms leads to an increase in their energetic arousal. Furthermore, negative affection is reduced through reward-gaining condition and is also increased through punishment condition. Individuals feel pleasure and convenience when faced with reward, while uncomfortable and nervous in the event of a punishment condition. In addition, offering a reward-based task to individuals with depressive symptoms in this study led to a reduction in tension arousal, thereby indicating that reward and punishment are significant sources for every behavior, and typically, individuals act such as to gain reward and avoid punishment. 
Overall, in the present study, we expected that the affective level of the participants would become positive in reward-gaining condition and would also perform the assigned task better in the reward-gaining condition than in the punishment condition. This expectation was largely confirmed, and the negative affection was reduced in the reward condition. Gaining reward creates pleasurable consequences, which leads to the consolidation of the desire and act in order to achieve reward, further leading to the improvement in affective levels among depressed individuals and reduction of negative affection in punishment condition. Therefore, psychotherapists are recommended to utilize rewards and reinforcers in the treatment of individuals with depression in order to improve their mood and affective levels as this enhances the effectiveness of therapeutic techniques on these individuals. 
Acknowledgments
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Conflict of Interest
The authors declare no conflicts of interest.

 

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