I have over 25 years experience working with children and for Children's Services in an Advisory role. ADHD never existed when I started teaching. There were other conditions that never existed then either, such as dyslexia and autism. Or at least they were not acknowledged or understood.
However I remember thinking 'this child really does try to spell or read and they genuinely just cannot hear the sounds and blend them in their heads' (dyslexia) and I remember asking the Ed Psych 'could it be that there are varying degrees of autism?' only to be told 'no'. Now we all know there is a continuum.
But I have never believed that ADHD is so commonplace. Yes, it does exist but it's rare. More often the attention deficit is due to upbringing; lack of consistency from parents and other significant adults, poor child rearing practices, bad diet, lack of exercise, and so on. It is interesting that your GS is able to concentrate under certain circumstances and his behaviour improves when he's with you lissieb. It is utterly disgraceful that he has been put on Ritalin.
When a political leader lies on their CV - can you trust them?


