A patient is brought with 6 months history of odd behavior. There is history of a family member having disappeared some years back. He seems to be talking to himself and sometimes laughing loudly. The likely diagnosis is:-

There is history of -Disorganized behavior -Hallucinations (talking to self and laughing loudly is most likely a result of patient hearing some voices and communicating with the voices) -The history of disappeared family member is again suggesting that some family member may have had a mental illness because of which either he got lost or committed suicide.All factors combined, the likely diagnosis is schizophrenia.