The point is people don't just suddenly become dicks. The OP knows someone for 12-13 years - more than half of his life - and notes rapid personality changes. They don't all take an assault rifle and shoot up a school but they are never the same.
I have seen this up close and personal. The son of a good friend was the nicest kid you ever wanted to know. Good student, ball player; when I was running the umpire program for the local Little League he was my best umpire. By the time he was 25 he was a total emotional wreck. His parents have him on medication but he is not capable of independent living and he can't hold a job. Guess what the diagnosis was?
I have seen this up close and personal. The son of a good friend was the nicest kid you ever wanted to know. Good student, ball player; when I was running the umpire program for the local Little League he was my best umpire. By the time he was 25 he was a total emotional wreck. His parents have him on medication but he is not capable of independent living and he can't hold a job. Guess what the diagnosis was?