If you mean they fried their brain then sure, that's bad and that's definitely one of the risks. But if it's just the Steve Jobs style "I see the world differe

If you mean they fried their brain then sure, that's bad and that's definitely one of the risks. But if it's just the Steve Jobs style "I see the world differently now" then to me it seems okay for the PhD to realign their goals because their values have changed. Of course, you can make the same argument that a heroin addicts values have changed, but the LSD isn't going to make you rob your family for your next hit.