Investigation of the effect of a single dose of stimulant medication (dexamphetamine 10mg or methylphenidate 20mg) on appetite and on fasting and postprandial levels of insulin, glucose, leptin and ghrelin in healthy adult volunteers.

Stimulant medication can be associated with slowing of growth in children with attention deficit hyperactivity disorder (ADHD), possibly by appetite suppression mediated by hormones such as leptin and ghrelin. Twelve healthy adult volunteers will have fasting blood tests for leptin, ghrelin, insulin and glucose, with these tests repeated after a meal. This will be done twice, once on medication (dexamphetamine or methylphenidate) and once on placebo. The effect of medication on food intake and alertness will be tested, together with subjects’ assessments of appetite and medication side effects.