That sounds like a skill issue
If you think you need mental illness to make art, you don't understand art very much and are just looking for an outlet for your pain
Instead of figuring out how to make yourself feel better on a regular basis, you wallow in sadness
And that's not say good art doesn't come from pain, but if all you do is focus on the misery you're just going to feel miserable
not everyone needs medication but when you're denying yourself getting better for the sake of some outside influence, that's just ego
also, accepting that negative emotions are a part of the human experience goes a long way into not feeling like the end of the world is happening when something bad happens