The Moderating Role of Tolerance of Ambiguity in the Association Between Borderline Personality Disorder, Risk-Taking Behaviors, and Decision-Making Styles

Abstract

Introduction and Aim: Borderline Personality Disorder (BPD) is characterized by emotional instability, impulsivity, maladaptive decision-making, and a heightened tendency toward risky behaviors. The present study aimed to investigate the effects of BPD on risk-taking behaviors and decision-making styles and to examine the moderating role of tolerance of ambiguity in these relationships.

Methodology: This cross-sectional descriptive-correlational study was conducted among individuals diagnosed with BPD who attended psychology clinics in District 16 of Tehran during 2025. Following data screening procedures, data from 84 participants were retained for analysis. The research instruments included the Youth Risk Behavior Survey (YRBS), McLain’s Tolerance of Ambiguity Scale (MAT), the General Decision-Making Style Questionnaire (GDMS), and the Borderline Symptom List-23 (BSL-23). Data were analyzed using path analysis in SmartPLS 4, and moderation effects were tested through bootstrapping procedures with 5,000 resamples.

Findings: The findings revealed that BPD had significant positive effects on avoidant (β=0.506, p<0.001), dependent (β=0.301, p=0.009), and spontaneous (β=0.471, p<0.001) decision-making styles, as well as on risk-taking behaviors (β=0.500, p<0.001). In contrast, BPD exerted a significant negative effect on rational decision-making (β=-0.261, p=0.005), whereas its association with intuitive decision-making was not significant. Moderation analyses demonstrated that the interaction between BPD and tolerance of ambiguity positively predicted rational decision-making (β=0.283, p<0.001) and significantly weakened the positive association between BPD and risk-taking behaviors (β=-0.133, p=0.039).

Conclusion: BPD is associated with greater engagement in risky behaviors, increased reliance on maladaptive decision-making styles, and reduced rational decision-making. Tolerance of ambiguity functions as a protective cognitive resource that buffers the adverse effects of BPD on rational decision-making and risk-related outcomes. Enhancing ambiguity tolerance may therefore represent an important therapeutic target for reducing maladaptive behaviors and improving decision-making processes among individuals with BPD.