Final answer:
Jason's improved psychological functioning after experiencing the trauma of a relative's violent death is an example of post-traumatic growth, a positive change that occurs in the aftermath of facing significant challenges.
Step-by-step explanation:
When Jason demonstrates improvements in psychological functioning that exceed his level of adjustment prior to the traumatic event of a relative's death due to violence, this phenomenon is known as post-traumatic growth. Unlike post-traumatic stress disorder (PTSD), which is a severe stress reaction to trauma, post-traumatic growth refers to a positive psychological change experienced as a result of the struggle with highly challenging life circumstances. It is characterized by a greater appreciation of life, improved relationships, a sense of increased personal strength, changed priorities, and a richer existential and spiritual life. This growth does not imply the absence of distress but indicates a significant positive change beyond the pre-trauma level.