This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Organic mental disorders, Subject name: Psychiatry
Amnesia typically occurs in 
Select and explain. 
A. Psychoneurotic states, B. Mania, C. Head injury, D. Schizophrenia
C: Head injury
Answer: C: Head injury 
Explanation: A variety of brain pathologies can give rise to severe memory impairment, the most common being the following: degenerative disorders (paicularly Alzheimer' disease and Huntington' disease); chronic alcohol abuse giving rise to Korsakoff' syndrome; traumatic head injury; temporal lobe surgery; encephalitis; cerebral vascular disorders (including subarachnoid haemorrhage resulting from ruptured aneurysms); anoxic brain damage (following, for example, myocardial infarction, carbon monoxide poisoning, or respiratory arrest); cerebral tumours. Reference: Shoer Oxford textbook of Psychiatry seventh edition, page no. 354.