From my experience there is not more children with anxiety or other mental health diagnoses.
There are more children recognised to have these conditions. The causes may be more up to date such as social media pressure or bullying, but these conditions existed in people long before the modern screen age.
I used to think it was normal to spend the whole day getting the courage to go out the house to the corner shop. Now I recognise that as an anxiety condition.
My husband felt suicidal as a teenager due to his separated parents domestic violence to each other. He stopped riding his bike to school because he had overwhelming urges to ride in front of a car on the road. We would now recognise this as depression.
I fully support schools teaching children and young people to recognise the risk factors that can cause mental ill health and identify the symptoms in themselves, friends and family so they can seek support. Yes it runs the risk of over self diagnosis with these conditions, but it will help many who really are struggling.
Yeah I also think there is too much pressure in primary schools especially to excel academically. School is telling me my 7 year old must be independent when his medical conditions mean he needs support to organise himself, in this regard I think schoolchildren with SEN can be set up to fail and this feeling of inadequacy brings the anxiety and fear of school settings.