Well, I was trying to phrase it positively because the original example I came up with was that if your entire family dies in a car crash, it's likely to cause an instant, long lasting negative change in your personality. Guess I swung it too far in the other direction haha.

But changes can be negative in a less drastic way too. For example, I'm sure the forced isolation of the past year has brought out depressive tendencies in a lot of people. In the face of that, we do need to be reminded that we can take charge and make positive changes in ourselves and that there are tools like meditation or CBT to help us (although it's certainly not so easy or works so universally as suggested in certain motivational books).

Worth noting is that many psychologists are calling for the end of solitary confinement in the prison system citing the adverse effects it has on inmates personalities.