A Good Friend of Your Parents Seems to Be Suffering

A good friend of your parents seems to be suffering from a psychological disorder. Your parents were not sure if the diagnosis was schizophrenia or unipolar depression. Which of the following would help to determine which disorder we are talking about?

A) If the level of GABA is extremely low
B) If the individual's cerebellum is enlarged
C) Whether the level of dopamine was unusually high or unusually low
D) Whether there were plaques affecting acetylcholine transport
E) If the individual is in a constant state of fear