Validation of the new DSM-5-TR criteria for prolonged grief disorder and the PG-13-Revised (PG-13-R) scale.

Although the concept of pathological grief dates back at least as far as Freud's "Mourning and Melancholia", there has been opposition to its recognition as a distinct mental disorder. Resistance has been overcome by evidence demonstrating that distinctive symptoms of prolonged grief disorder (PGD) - an attachment disturbance featuring yearning for the deceased, loss of meaning and identity disruption - can endure, prove distressing and disabling, and require targeted treatment. In acknowledgement of this evidence, the American Psychiatric Association Assembly has recently voted to include PGD as a new mental disorder in the DSM-5-TR. We tested the validity of the new DSM criteria for PGD and of an adapted version of our PG-13 scale, the PG-13-Revised (PG-13-R), designed to map onto these criteria, using data from investigations conducted at Yale University (N=270), Utrecht University (N=163) and Oxford University (N=239). Baseline assessments were performed at 12-24 months post-loss; follow-up assessments took place 5.3-12.0 months later. Results indicated that the PG-13-R grief symptoms represent a unidimensional construct, with high degrees of internal consistency (Cronbach's alpha = 0.83, 0.90 and 0.93, for Yale, Utrecht and Oxford, respectively). The DSM PGD diagnosis was distinct from post-traumatic stress disorder (phi=0.12), major depressive disorder (phi=0.25) and generalized anxiety disorder (phi=0.26) at baseline. Temporal stability was remarkable for this diagnosis (r=0.86, p<0.001). Kappa agreement between a PG-13-R threshold symptom summary score of 30 and the DSM symptom criterion for PGD was 0.70-0.89 across the datasets. Both the DSM PGD diagnosis and the PG-13-R symptom summary score at baseline were significantly associated (p<0.05) with symptoms and diagnoses of major depressive disorder, post-traumatic stress disorder and/or generalized anxiety disorder, suicidal ideation, worse quality of life and functional impairments at baseline and at follow-up, in the Yale, Utrecht and Oxford datasets. Overall, the DSM-5-TR criteria for PGD and the PG-13-R both proved reliable and valid measures for the classification of bereaved individuals with maladaptive grief responses.