In current clinical science, complicated grief captures a larger number of people in that upper end of the continuum (about 1 or 2 in 10) than does prolonged grief disorder (between 1 and 10 in 100).
O’Connor distinguishes complicated grief from the more restrictive diagnostic category of prolonged grief disorder by prevalence, situating both on a continuum of chronic grieving.
, The grieving brain the surprising science of how we learn, 2022thesis