Childhood obesity remains through adulthood in main cases, and is associated with an early increase of cardiovascular risk and an excess mortality in young adults due to stroke and cancer.~Bariatric surgery is very rare in France for children and can cause severe complications. Long term effects are still unknown.~Topiramate is already use in thousands of children in neurology, its effects are already well known, and no lethal complication is reported.~The hypothesis is that Topiramate associated with standard treatment of obesity is more effective than standard treatment alone.~This will be a 4.5-years, randomized, double-blind, placebo-controlled, clinical trial of topiramate (9 months) vs placebo (9months) for Body Mass Index reduction in 160 adolescents (ages 9-17 years old) with severe obesity.~The main objective is to evaluate the efficacy of Topiramate on the decrease of Body Mass Index compared to placebo at 9 months.~The secondary objectives are to evaluate:~the decrease of Body Mass Index Z-score~the tolerance of Topiramate~the effectiveness of Topiramate on weight decrease and decrease of Body Mass Index and Body Mass Index Z-score at 1, 3 ,4 and 6 months~the effectiveness of Topiramate on eating behaviour, physical activity, calculated with validated questionnaires and scales at 6 and 9 months~the pharmacokinetic of Topiramate in obese children and adolescents
The purpose of this study is to evaluate the efficacy of Topiramate on the decrease of Body Mass Index compared to placebo at 9 months.