My GS has ADHD and was on medication which definitely helped him focus and concentrate in class - his grades improved!! However at age 14 he said he no longer wanted to take them - one side effect for him was loss if appetite/ not enjoying meals. Parents now waiting got GCSE results but are not expecting good grades. He is starting a college course next month. I suspect he will be happier out of school , so it's now onwards and upwards for him. He is a delightful young man and his condition is improving as he matures. Don't worry !