Introduction: The prevalence of Internet gaming disorder (IGD) ranges from approximately 2% to 27.5% in the world population and 5.5% in the Polish population. Research findings indicate that IGD may be associated with depression, ADHD, anxiety, autism spectrum, and aggressive behaviours. However, there is a lack of research on the relationship between IGD and borderline personality disorder and psychological pain (psychache). The aim of this study is to examine the relationships between IGD and symptoms of anxiety, depression, psychological pain, borderline personality disorder and determining the role of psychological pain as a mediator of the above-mentioned links.; Methods: A sample of Polish gamers (n=201) was assessed using clinical scales (HADS, IGD-20, BPD Checklist) to evaluate the severity of depression, anxiety, IGD, and borderline personality symptoms. Additionally, the psychological pain scale was administered to assess relationship with IGD via mediation models. Results: Regression analysis in a mediation model revealed that IGD significantly predicted anxiety and depression, while borderline personality disorder was a significant predictor of IGD. Moreover, a bidirectional relationship between IGD and psychological pain had been demonstrated–IGD was a significant predictor of psychological pain and vice versa. Psychological pain also mediated the relationship between IGD and anxiety and depression, as well as the relationship between borderline personality symptoms and IGD. Conclusions: In the diagnostic and therapeutic process of people suffering from IGD, the co-occurrence of IGD with psychological pain, depression, anxiety and borderline personality disorder should be considered. Further scientific exploration is required to assess the associations between IGD and clinical variables and psychological pain.