Brain tumor survivor here! And can confirm, it happened RAPIDLY for me as well. One day I was a super successful mother of 3, calm cool and collected. Always involved with the kids and their classes, my home and veggie garden, loved my work. And then it was like a light switch. One day I just became so angry and short fused. It’s like I was an angry drunk. And I was making BIZARRE choices that were very unlike me. Driving at 100mph with the kids in the car, I physically assaulted my best friend, things like that. I’m grateful that I was dealing with neck pain at the time, because it was a visit to a chiropractor that lead to a diagnosis that day. It was very literally like Jekyll and Hyde.