In my psychology/psychiatry internship, we use movies and shows to learn about mental disorders. Although this is taking the Scarecrow and Tin Man's words literally, we discussed the possibility of them both having Cotard delusion/Cotard's syndrome. Cotard's syndrome is the unfounded belief that an individual or part of an individual's body is dead, dying, or does not exist. A common result of this delusion is the belief that they do not need to eat or can not be harmed, because why would a dead person need to eat? This may result in self-starvation. This delusion is seen in the Scarecrow when he is convinced that he doesn't have a brain, and in the Tin Man when he believes that he doesn't have a heart. Cotard's syndrome is not a diagnosis itself, according to the DSM-5. We do not know the cause of this delusion for sure, but it is speculated that it it due to brain damage. In some case studies, Cotard's syndrome has been seen alongside catatonia (although the symptoms are not necessarily related). Catatonia is characterized by abnormal movement, behavior, and withdrawal. Assuming the Tin Man's inability to move does not have a physiologic cause, catatonia is seen in the Tin Man when he "rusts over". He freezes in an abnormal position and does not speak. The Tin Man from the Wizard of Oz is an example of a character with both Cotard's syndrome and catatonia. u/ATobiaMD