Final answer:
In the most common type of dissociative amnesia, a person typically loses memory for some, but not all, events related to the trauma, which is categorized as retrograde amnesia.
Step-by-step explanation:
In the most common type of dissociative amnesia, a person loses memory for some but not all of the events related to the trauma. This type of memory loss is generally understood to be a form of retrograde amnesia, where individuals cannot remember certain aspects or details of their past. This occurs due to psychological trauma and is different from anterograde amnesia, which is memory loss for events that occur after brain trauma and affects the ability to form new memories.