Mainly, however, we care about the meaning of "outsider" art for "insider" that is, for the presumably healthy persons who populate our classes.
Here the clinical experience for Freud, Jung, and depth psychologist in general is relevant ; it suggests that the behavior of psychotics, neurotic, and so-called "normal" differ in degree but not in kind.
In other world, every human being occupies a point on a single behavioral continuum.
For some of us, that point is not especially fixed, which make for an " interesting" artistic scene.