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What is A middle aged man presented with pain in back, lack of interest in recreational activities, low mood, lethargy, decreased sleep and appetite for two months. There was no history suggestive of delusions or hallucinations. He did not suffer from any chronic medical illness. There was no family history of psychiatric illness. Routine investigations including haemogram, renal function tests, liver function tests electrocadiogram did not reveal any abnormality. This patient should be treated with - and explain in detail?
This patient has (for 2 months)

i) Lack of interest                  
ii) Low mood 
 iii) Loss of energy / fatigue (lethargy)     
iv) Decreased sleep 
v) Decreased appetite          

Diagnosis is major depression → Antidepressant should be given. Amongst the given options only sertaline is antidepressant.