I wonder why is it that we didn't have any kids who were standing on their chairs, shouting and wandering the classrooms during examination when I was attending

I wonder why is it that we didn't have any kids who were standing on their chairs, shouting and wandering the classrooms during examination when I was attending primary school in the 80's. I have never heard of such a case and we had a decent sized school of about 150 children of the same age. Multiply that by 8 grades and that is 1200 children and surely these symptoms must have manifested in at least some of the children if ADHD existed back then also.