Which disorder is characterized by an inability to remember recent past experiences and functional impairment in daily activities?

The disorder characterized by an inability to remember recent past experiences and functional impairment in daily activities is Dissociative Amnesia. This condition primarily affects an individual's memory, particularly for personal information or significant events, often as a result of trauma or stress. In Dissociative Amnesia, the person often cannot recall important autobiographical details, which can lead to notable disruption in their ability to engage in everyday tasks and relationships.

This memory impairment is distinct from other disorders, such as Dementia, which typically involves more generalized cognitive decline over time rather than specific gaps in memory related to trauma or stress. While Major Depressive Disorder may lead to difficulties in concentration and memory, it does not primarily manifest as a lack of memory for specific recent events. Similarly, PTSD can involve memory issues, particularly related to traumatic events, but it does not typically feature the same kind of selective memory loss for recent experiences as seen in Dissociative Amnesia. Thus, the key features and causes of memory loss in Dissociative Amnesia make it the most fitting answer to the question.