Prolonged grief disorder (PGD) is a diagnostic entity now included in the International Classification of Diseases 11th Revision (ICD-11) and soon to appear in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition, text revision (DSM-5-TR). A characteristic feature of PGD is distressing, disabling yearning that persists a year or more after the loss. Other characteristic symptoms include disbelief and lack of acceptance of the loss, emotional detachment from others since the loss, loneliness, identity disturbance, and sense of meaninglessness. In this review, we detail psychiatric views on grief and their evolution over the twentieth century. We then discuss the development of diagnostic formulations for disordered grief, which culminated in PGD's status as a mental disorder in the DSM. After summarizing recent evidence that may suggest that PGD is linked to the neural reward system, we suggest further areas of research. In particular, we note the need for studies that extend the evidence base concerning PGD across cultural and sociodemographic boundaries and that investigate novel treatments.
Keywords: bereavement; complicated grief; grief; mental disorders; prolonged grief disorder; reward system.