Sooner or later, they peak. Yet they have developed very high expectations. They are then in a position where they're subject to intense scrutiny, but they can't do any better. They can only get worse. It's a prescription for depression.
Celebrities have a lot of health problems.
In many cases, there is a tendency toward early suicide. Celebrities also suffer from high rates of alcoholism and stress. Fame is a double-edged sword. On average, it's not very good for your health. Warhol was an interesting and, in my view, underrated thinker on fame.