This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
Amnesia is found in - 
Select and explain. 
A. Head injury, B. Mania, C. Schizophrenia, D. Psychiatric state
A: Head injury
Answer: A: Head injury 
Explanation: Amnesia is often caused by a traumatic injury to brain, such as a blow to the head. Other causes are degenerative brain diseases (e.g., Alzheimer's disease), blockage of cerebral blood vessels, infectious diseases, chronic alcoholism, and psychological (dissociative amnesia).