This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mood disorders, Subject name: Psychiatry
All are required to diagnose major depression except 
Select and explain. 
A. Depressed mood, B. Insomnia, C. Nihilistic Ideas, D. Decreased concentration
C: Nihilistic Ideas
Answer: C: Nihilistic Ideas 
Explanation: Depression is a mental disorder characterized by group of symptoms The symptoms are characterized as major and minor symptoms MAJOR SYMPTOMS pervasive low mood Anhedonia ( loss of interest in previous pleasurable activities) Fatiguibility MINOR CRITERIA Hopelessness Inappropriate guilt Suicidal ideas Decreasedconcentration Loss of confidence and sence of inferiority Sleep disturbance Appetite disturbance Psychomotor inhibition These symptoms have to be present for a duration of 2 WEEKS