Interpersonal psychotherapy for comorbid prolonged grief disorder and persistent depressive disorder in a Japanese patient: A case report.

Background: Prolonged grief disorder (PGD) is a new diagnostic entity. However, treatment for PGD is not yet available. Interpersonal psychotherapy (IPT) may be effective for PGD. Case Presentation: A single 27-year-old Japanese woman lost her brother to suicide. However, she did not express her grief to anyone or visit a psychiatric clinic. After experiencing strong depressive symptoms triggered by work stress, she visited a psychiatric clinic, where she was diagnosed with depression as well as PGD. Through pharmacotherapy, her depressive symptoms improved, but no improvement was noted in her PGD symptoms. She therefore began IPT for PGD at our hospital, 5 years after her brother's suicide and after 4 years of PGD symptoms. In the introductory phase of IPT, she was diagnosed with comorbid persistent depressive disorder (PDD). After this diagnosis, through psychoeducation on PDD, she could identify the symptoms that reflected her personality traits as "PDD symptoms." Furthermore, she could affirm her positive and negative feelings and share them with others. Consequently, the grieving process was facilitated, and her interests and relationships were re-established. Her PGD and PDD symptoms improved. Conclusion: IPT may be effective for PGD comorbid with PDD among Japanese.