Ramu, a 22 year old single unmarried man is suffering from sudden onset of 3rd person hallucination for the past 2 weeks. He is suspicious of his family members and had decreased sleep and appetite. The diagnosis is:

B i.e. Acute psychosis As you know 3rd person hallucination are very much characteristic of schizophrenia; but for making a diagnosis of schizophrenia, atleast 6 months duration is required. So this can't be schizophrenia. The consciousness & orientation (recognizes family members) is normal, so acute delirium is ruled out. Now if we concentrate upon symptoms- 3rd person hallucination is a characteristic feature of schizophrenia; but decreased appetite & sleep are not the essential criteria of mania (essential criteria is persistently & abnormally elated mood). Last but not the least you should know that diagnostic criteria of schizophrenia, schizophreniform disorder, acute psychosis (delusional), brief psychotic disorder are same & only differentiation is duration of symptoms In Brief psychotic disorder <1 monthQ (duration of disturbance) In Acute delusional psychosis <3 monthsQ In Schizophreniform disorder < 6 months 1 duration of disorder In Schizophrenia > 6 monthsQ