Role of Behavioral Activation and Inhibition Systems in Symptoms of Major Depression Disorder Regarding the Mediating Role of Cognitive Bias

Background: This study aimed to investigate the role of the behavioral activation and inhibition systems in symptoms of major depressive disorder, considering the mediating role of cognitive bias. Materials and Methods: The statistical population of this descriptive-correlational research was all the students of Ahvaz Azad University, Ahvaz, Iran during the academic year 2015-16. In total, 300 students were selected using the multistage sampling method, and finally, 279 students participated in this research. Data were collected using the Behavioral Inhibition/Activation Systems Scale, the Dysfunctional Attitudes Scale, and the Beck Depression Inventory. The collected data were analyzed using multiple regression analysis, coefficient correlation, and structural equation modeling in SPSS (version 22), Lisrel (version 8.80), and Mplus (version 6.12) software. Results: The results showed that cognitive bias mediated the influence of behavioral inhibition and activation systems on depressive disorder. Based on the findings, all of the direct and indirect effects of the model were significant. The model itself had a suitable index of fit, and cognitive bias significantly affected major depressive disorder symptoms. In the final model, the direct effect of the behavioral inhibition system was added to depression. Moreover, the indirect effect of the behavioral activation system on depression was not significant. Conclusion: The proposed model had an acceptable fitness to the result and was an essential step in recognition of the significant factors of major depressive disorder. It can be useful as a model for designing stress management programs and decreasing major depression disorder.