The question as posed is meaningless. Prednisone is an immune system depressant, and in some cases the risk is worth the benefit. As stated many people become monsters when they are on this steroid. This is because whenever the immune system is depressed, the body develops a different personality. Genetically, this has survival value. Imagine a human wounded and unable to defend themselves. A verbally agressive action might keep a predator away. In the case of a severe asthmatic attack, oral predinsone may save a person's life. On the other hand long term use causes a predisposition to malignancies and all kinds of infections.
Taking it for what? I took it for a severe poison ivy allergic reaction once. It worked for the posion ivy. But I had a MASSIVE personality change. I'm pretty sure I turned into satan during that time. It was awful and I refuse to take it again. Plus, I couldn't sleep on it.