Evaluating the Effect of Melatonin on Positive and Negative Symptoms of Schizophrenic Patients: A Randomized Placebo-Controlled Study oleh Forouzan Behrouzian, Leila Abdi, Masoumeh Nazarinasab, Amirali Moghaddam Sadegh, Sanam Anoosheh, Maryam Moradi