It could be said that psychoanalytical disorders (hysteria, perversion, psychosis, etc.) revolve around a subject’s predisposition towards demanding the truth within fiction.
Everybody faces a plethora of fictions and illusion each and every day, we all ‘suspect’ hidden truths everywhere. The hysteric, with her constant questioning, can never rest until the answer is given; unfortunately, she is never satisfied with any truth. The obsessive, on the other hand, cannot accept any other truth except the one he believes in, hence the manic-compulsive behaviour. The psychotic, of course, faces no illusions: He knows without a doubt that the beef pepperoni pizza on the plate is really an alien weapon.
For more ideas along this line, Disorderly Conduct: Neurosis, Psychosis and Perversion in Political Malaysia.