Fatemeh Hosseini Kasnavieh - Department of Psychiatry, Research Center of Addiction and Behavioral Sciences, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Hassan Rezaeipandari - Dpartment of Health Education and Promotion, Faculty of Health Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
Mehdi Hadadzadeh - Department of Cardiac Surgery, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Mahmood Vakili - Health Monitoring Research Center, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Fatemeh Hosseini Biouki - Department of Psychiatry, Ziaei Hospital, Shahid Sadoughi University of Medical Sciences, Yazd, Iran

Introduction: Delirium has been considered as the most common cognitive disorder after major surgery. Melatonin therapy is effective in reducing the incidence of delirium after open heart surgery with pain relief mechanism and adjustment of the sleep cycle and the absence of specific side effects. This study was conducted to determine the effectiveness of melatonin on prevention of delirium after coronary artery bypass surgery.   Methods: The double blind randomized controlled clinical trial  recruited 140 patients, equally decided, who underwent  coronary artery bypass surgery in Afshar Hospital, Yazd city, 2016. All participants of the two groups were evaluated for the presence of delirium  on the day of surgery and three days after by the Confusion Assessment Method for ICU (CUM-ICU). Respectively, The intervention and control group received 3 mg melatonin and 3 mg placebo orally before and after the operation. Data were analyzed by Chi-square, T-test, paired t-test and Cochran tests.   Results: The incidence of delirium in the melatonin and the control group was 35.7% and 5.7% on the day of operation, 68.6% and 31.4% three days after the operation, respectively. The results showed that there was a significant difference in the frequency of cognitive test of CAM-ICU on day of surgery and three days after surgery between the two groups (p <0.001).   Conclusion: Despite the efficacy of melatonin therapy in reducing delirium, further studies on the effects of other effective drugs on the treatment of delirium, such as antipsychotics and receptor blockers, should be considered.

Melatonin, Delirium, Surgery, Older Adults, Clinical Trial