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
Sudden onset of hallucinations in a 35 year old man with no previous history & family history of schizophrenia may be due to - 
Select and explain. 
A. Substance abuse, B. Schizophrenia, C. Frotterism, D. Depression
B: Schizophrenia
Answer: B: Schizophrenia 
Explanation: This patient has -

Sudden onset of hallucination
Previous history negative (Patient was normal before onset of hallucination)
Relevant family history

In Schizophrenia, Sudden onset of hallucination may be the first symptom and patient may have a positive family history.
About other options 

In depression, there should be a history of depressive symptoms before the onset of hallucination.
In substance abuse, there should be a history of substance abuse.