The diagnostic criteria for a variety of mental disorders include symptoms that involve impairment in the ability to make rational judgments. The most obvious of these would seem to be the delusions that are the most common symptom on which psychotic disorders are diagnosed. In DSM-IV, “
delusion” is defined as: “A false belief based on incorrect inference about external reality that is firmly sustained despite what almost everyone else believes and despite what constitutes incontrovertible and obvious proof or evidence to the contrary.”
Major depressive disorders and various
anxiety disorders include symptoms indicating impairments in the ability to concentrate.
Personality disorders entail behaviors that “deviate markedly from the expectations of the individual's culture,” as manifested first and foremost in “cognition” or “the ways of perceiving and interpreting self, other people and events”.
At least theoretically, impairment in the ability to reason correctly is not a desirable trait in a jury member. Of course, these days, depending on the case, lawyers are often more interested in choosing jury members who are susceptible to suggestion, are easily distracted and manipulated by irrelevancies, or who adhere to a particular political ideology.
Nevertheless, should having a mental disorder be recognized as a valid for-cause reason for excluding a person from a jury? If not, why not?