I think that's one dangerous thing to think: that one needs to be mentally tortured to be a great artist. A fledgling artist has to deal with so many other problems: poor and irregular pay, lack of recognition, lack of steady work, and so on. Add mental illness to this mix, and it's a difficult life, to say the least. Sometimes people suggest that an artist must be mentally tortured and anti-social to become great. That is misinformed and sadistic.