This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Schizophrenia Spectrum and Other Psychotic Disorders, Subject name: Psychiatry
A 20 year old boy complains of hearing voices and aggressive behavior for last 2 days. He had persistent high fever before the onset of these symptoms. The family members repo that he has been muttering to self and gesticulating as if he is talking to someone. There is no history of any past psychiatric illness. The likely diagnosis is:- 
Select and explain. 
A. Dementia, B. Acute psychosis, C. Delirium, D. Delusional disorder
B: Acute psychosis
Answer: B: Acute psychosis 
Explanation: Acute Psychosis =Duration of symptoms < 1 month. =Often preceeded by stressor (fever being a common stressor, hence don't get confused.) =Symptoms similar to schizophrenia (Delusions, hallucinations, disorganisation) =often resolve completely Treatment: Antipsychotics and/or Benzodiazepines as and if needed. In this case if the history also mentioned disturbances of consciousness or history of disorientation, the likely diagnosis would be delirium. Hallmark of Delirium Impaired consciousness Develops quickly Fluctuating course with lucid intervals Hallmark of Dementia Loss of memory and intellectual abilities Develops slowly Progressive downhill course