Introduction: The present study was conducted with the aim of investigating Borderline personality disorder, which often appears during adolescence, is characterized by profound neurological, psychological, and social changes; therefore, the present study was conducted with the aim of investigating the effectiveness of group schema therapy on emotion regulation and generalized anxiety disorder in adolescent girls with borderline personality.
Methods: The research method was a semi-experimental study with a pretest-posttest design with a control group. The statistical population of the study was all adolescent female students aged 15 to 18 years old in high school in Shahrood city in 1402, who were selected through stage sampling with the Borderline Personality Disorder (BPI) screening and diagnostic questionnaire and randomly assigned to two experimental and control groups (2 groups of 15 people). The measurement tools included the Maudsley Obsessive-Compulsive Inventory, the Generalized Anxiety Disorder Questionnaire (GADQ), and the Gross and John Emotion Regulation Scale (2003). Schema therapy sessions were implemented based on the schema therapy method designed and developed by Young et al. (2003). Data analysis was performed using descriptive and parametric inferential analyses such as one-way ANOVA, repeated measures test, and Bonferroni post hoc test using SPSS-24 software.
Results:  The results showed that there was a significant difference between the three stages of the test of emotion regulation and generalized anxiety disorder components in the experimental group (p<0.001); however, there was no significant difference between the three stages of the test in the variables of emotion regulation and generalized anxiety disorder in the control group (p<0.05).
Conclusion: According to the results of the study, it can be said that group schema therapy is effective on emotion regulation and generalized anxiety disorder in adolescent girls with borderline personality. It is suggested that the schema therapy approach be used to improve and treat these two variables.