Open Access

Octavia Harrison, Sabine Windmann, Rita Rosner, Regina Steil

• Objectives: Interpersonal factors, such as impairments in social interaction or lack of social support, have an important share when it comes to the development, maintenance, and progression of various mental disorders. Methods: Individuals suffering from prolonged grief disorder (PGD) and matched bereaved healthy controls (n = 54) underwent a thorough diagnostic procedure, further completed the Inventory of Interpersonal Problems (IIP-D-32), and participated in a finitely iterated prisoner's dilemma (FIPD). Results: Individuals suffering from PGD reported significantly more interpersonal problems. Both groups behaved differently in the FIPD with healthy controls being more carefully, adapting their behavior more flexible, whereas PGD patients displayed a lower responsiveness, which may indicate an inability to adapt to changes in relationships. Conclusion: We conclude that interpersonal problems appear to be a relevant feature of PGD. Future studies need to clarify the causal relation behind this link, and should also include measures of attachment, social support, and disconnectedness.