POMC and psychotic disorder: Direct correlation between stress and psychosis has been suggested for several reasons: (i) negative symptoms severity are related to ACTH and/or cortisol plasma level in patients with schizophrenia [4, 69]; (ii) acute stress triggers psychotic symptoms in patients with schizophrenia [70, 71]; (iii) atypical antipsychotics decrease HPA activity leading to a reduction in ACTH as well as cortisol secretion in patients with schizophrenia [72]; (iv) withdrawal of atypical antipsychotics of patients with schizophrenia increases cortisol plasma level and it is related to negative symptoms [73].