This article counters recent attempts by literary scholars to offer a psychiatric diagnosis of late medieval mystics such as Margery Kempe and Julian of Norwich. It demonstrates that the diagnostic tools (DSM-IV, ICD10) used by scholars to describe medieval mystics' symptoms are not employed correctly, that the nomenclature they use is culturally and historically dependent, and that one should rather understand mystics' behaviour in light of the medieval mystical tradition instead of trying to take it out of its visionary and religious context.