Objectives:
This study sought to determine whether the symptoms of prolonged grief disorder (PGD) according to ICD-11 and DSM-5-TR have a unifactorial structure. Second, we sought to determine the sociodemographic and loss-related correlates of PGD symptom severity according to ICD-11 and DSM-5-TR.

Methods:
People who had lost a spouse (N = 144) in the past six months were examined using the Polish versions of the Prolonged Grief Disorder-13 scale (PG-13) and Inventory of Complicated Grief (ICG). Selected PG-13 and ICG items were included in the analyses to cover the PGD criteria according to ICD-11 and DSM-5-TR.

Results:
Confirmatory factor analyses supported the one-dimensional structure of both sets of symptoms of the disorder. Briefer time since loss and loss due to an accident were associated with PGD symptom severity according to both ICD-11 and DSM-5-TR.

Conclusions:
PGD is a one-dimensional and internally consistent psychopathological syndrome. Widows and widowers who have recently lost their spouse due to an accident may be at especially heightened risk of developing severe levels of PGD symptoms.