Appetite suppression is one of the most common side effects of methylphenidate (MPH), which is used for treatment for attention-deficit hyperactivity disorder (ADHD). Relation of appetite and leptin is well known but there is no report regarding MPH use and leptin. In this study we compared the baseline leptin levels of ADHD children with the controls and studied the interaction between MPH and leptin-insulin level in ADHD children under MPH treatment. The major funding of this study is that at a total daily dose of 0.6 mg/kg short-acting MPH treatment, one does not observe significant side effects related to appetite suppression side metabolic features as measures via body mass index. insulin and leptin levels. Thus this range seems to be safe in developing ADHD children with minimum side effects regarding appetite for short term treatment. (c) 2007 Prous Science. All rights reserved.