Does mental rigidity cause psychological problems?
I've read that a tendency to "jump to conclusions" has an impact on certain psychological afflictions, such as having delusions.  As you may know, the definition of a delusion is as follows (this is just from Google dictionary):


  an idiosyncratic belief or impression that is firmly maintained despite being contradicted by what is generally accepted as reality or rational argument, typically a symptom of mental disorder.


I am assuming that that sort of uncritical thinking is at least part of what you meant by "mental rigidity."