Tehran University of Medical Sciences Iranian Journal of Psychiatry 1735-4587 7 3 2012 09 15 114 9 Seyed-Ali Mostafavi Department of Nutrition & Biochemistry, School of Public Health, Tehran University of Medical Sciences. Mohammad Reza Mohammadi Payam Hosseinzadeh Mohammad Reza Eshraghian Shahin Akhondzadeh Mohammad Javad Hosseinzadeh-Attar Elham Ranjbar Seyed Mohammad-Ali Kooshesh Seyed-Ali Keshavarz Address: Tehran University of Medical Sciences, Faculty of Health, Department of Nutrition and Biochemistry Zip code: 141556446 2015 10 14 Objective: It is postulated that ritalin may adversely affect sleep, appetite, weight and growth of some children with ADHD. Therefore, we aimed to evaluate melatonin supplementation effects on dietary intake, growth and dev elopment of children with ADHD treated with ritalin through circadian cycle modification and appetite mechanisms . Method: After obtaining consent from parents, 50 children aged 7-12 with combined form of AD/HD were randomly divided into two groups based on gender blocks: one received melatonin (3 or 6 mg based on weight) combined with ritalin (1mg/kg) and the other took placebo combined with ritalin (1mg/kg) in a double blind randomized clinical trial. Three-day food record, and standard weight and height of children were evaluated prior to the treatment and 8 weeks after the treatment. Children’s appetite and sleep were evaluated in weeks 0, 2, 4 and 8. Hypotheses were then analyzed using SPSS17.  Results: Paired sample t-test showed significant changes in sleep latency (23.15±15.25 vs. 17.96±11.66; p=0.047) and total sleep disturbance score (48.84±13.42 vs. 41.30±9.67; p=0.000) before and after melatonin administration, respectively. However, appetite and food intake did not change significantly during the study. Sleep duration and appetite were significantly correlated in melatonin group (Pearson r=0.971, p=0.029). Mean height (138.28±16.24 vs. 141.35±16.78; P=0.000) and weight (36.73±17.82 vs. 38.97±17.93; P=0.005) were significantly increased in melatonin treated children before and after the trial . Conclusion: Administration of melatonin along with ritalin improves height and weight growth of children. These effects may be attributed to circadian cycle modification, increasing sleep duration and the consequent more growth hormone release during sleep. https://ijps.tums.ac.ir/index.php/ijps/article/view/238 https://ijps.tums.ac.ir/index.php/ijps/article/download/238/234