Background & Objectives: Depression is one of the most common mental disorders; its growing prevalence is becoming a global concern. Depression in children and students is one of the essential topics in research psychology. In general, depression can lead to academic failure and impairment of occupational, family, and social functioning, which directly and indirectly imposes high costs on society. Among the cognitive components of depression, cognitive inhibition has a significant share. Cognitive inhibition is active processing that prevents unwanted internal and external stimuli from entering the information processing system. On the other hand, one of the most important abilities in adolescence is tolerating distress. Acceptance and commitment therapy (ACT) is one of the new therapeutic approaches that have an auspicious effect on depression. Given that depression exists among students and cognitive inhibition and distress tolerance can affect their educational process and daily life, this study aims to determine the effectiveness of ACT on cognitive inhibition and distress tolerance of depressed female high school students.
Methods: The present research is a quasi–experimental study with a pretest–posttest design with a control group. The statistical population included all secondary school girls with depression referred to Rah–e Bartar Psychological Services Clinic in Tehran's District 4, Iran, for treatment from March to September 2019. The statistical sample consisted of 30 students randomly assigned into experimental and control groups (15 people in each group). The inclusion criteria were being 14 to 17 years old, having depressive disorder confirmed thorough diagnostic interview, gaining a score of more than 19 on the Beck Depression Inventory, lacking acute medical illnesses and brain damage, and not attending training sessions. The exclusion criteria were non–participation in training sessions and lack of informed consent. The Structured Clinical Interview (Lobbestael et al., 2011), Beck Depression Inventory–II (Beck et al., 1996), Anxiety Tolerance Scale (Simons & Gaher, 2005), and the White Bear Suppression Inventory (Wegner & Zanakos, 1994) were used to collect study data. During the intervention phase, the experimental group underwent eight 90–min sessions of ACT by Hayes et al. (2012), but the control group did not receive any intervention. To analyze the data, descriptive (mean and standard deviation) and inferential statistics (the Chi–square test [to compare the distribution of educational variables in the two groups], multivariate and univariate analysis of covariance) were performed in SPSS software version 24. The significance level of the tests was considered α = 0.05.
Results: The results showed that ACT significantly reduced cognitive inhibition (p<0.001) and increased the components of distress tolerance, including tolerance (p<0.001), absorption (p<0.001), evaluation (p<0.001), and adjustment (p<0.001) in depressed students in the experimental group compared to the control group. Also, the effect size indicates the effect of ACT on reducing the cognitive inhibition variable (0.428) and increasing the variables of distress tolerance of high school students with depression, including tolerance (0.396), absorption (0.326), evaluation (0.267), and adjustment (0.229).
Conclusion: Based on the findings, acceptance and commitment exercises can improve the psychological state of depressed students. Therefore, ACT is one of the effective non–pharmacological therapies in the psychological management of depressed patients, and it is necessary to consider it an effective treatment along with drug therapies.