Background and Objective: Cognitive and physiological components such as intolerance of uncertainty, cognitive avoidance and brain/behavior systems have a significant impact on generalized anxiety disorder. The mentioned components are considered as the main causes of the emergence and persistence of this disorder. The aim of this study was to compare brain/behavioral system activity, intolerance of uncertainty and cognitive avoidance among individuals with generalized anxiety disorder and normal people.

Materials and Methods: The participants of this study were randomly chosen from Zanjan University students and were composed of two major groups of 45 patients with generalized anxiety disorder and 45 normal individuals. Short scale generalized anxiety disorder (GAD-7), Gray-Wilson Personality Questionnaire (GWPQ), intolerance of uncertainty scale (IUS) and cognitive avoidance questionnaire (CAQ) were given to the subjects. Later, those who had scored higher on the short scale generalized anxiety disorder (GAD-7) and were diagnosed with generalized anxiety disorder using a structured clinical diagnostic interview based on DSM (SCID-I) were categorized as diagnosed with GAD. The normal individuals group consisted of those who were not diagnosed with any kind of mental disorder using a structured clinical diagnostic interview based on DSM (SCID-I). Data analysis was performed using multivariate analysis of variance (MANOVA) and regression analysis.

Results: Between cognitive components, intolerance of uncertainty in the group with generalized anxiety disorder was significantly higher than the normal group (p< 0/05). Between physiological parameters, a subscale of behavioral inhibition system in individuals with generalized anxiety disorder was significantly higher than the normal group (p< 0/05).

Conclusion: Intolerance of uncertainty and behavioral inhibition system proved to be good parameters for the prediction of generalized anxiety disorder. Furthermore, the intolerance of uncertainty, behavioral inhibition system, and behavioral activation system were different in patients with generalized anxiety disorder and normal individuals.