hi there and welcome. i would only think that superstitious beliefs could only be defined as a disorder if it were to interfere with "day to day" living. ANYTHING that inteferes with day to day living, and prevents a person from living and doing as they could/would, can be deemed a disorder.

for example, dissociation is a common life experience. however, when it becomes great and often, it inteferes with life and is considered a disorder.

in the same right, if superstitious belief stopped you from living the life that you could without it and prevented you from doing what you need to, i would think it a disorder. if it doesn't intefere often, then not.

peace and safety,

kd