I once wrote a short story about being challenged to stake my identity (my personality) somewhere along the spectrum between mania and depression; it was published in an ultra-low-budget journal of horror fiction in Massachusetts. I'm glad it was pre-internet because the story got pretty ugly.

Now after 25 years of disease and meds, I either have a compromised personality with no memory of who I had been and what it felt like before I got sick, or the essence of my personality has emerged through the disease and the meds and the trauma, and survived. I've had enough meds so I that I have no idea what happened, nor do I particularly care.

Personality could be a victim of mental illness: one of the best things I've seen written about mental illness is that it "damages identity."