My cousins youngest was a bit like Zara, he went through a nightmare stage and it was a shock after two easy kids, my cousin corrected behaviour every time and worked with the preschool and primary school and he’s a different child. My cousin always credits the preschool for having the hard chat and putting changes into place before he got a name for himself in the school. Sometimes kids need a little more discipline than others not chasing a diagnosis. That child now is a fantastic child and I love spending time with him.