I absolutely believe this to be true - but I don't think you'd be able to get any decent stats as the mental health support services are in such crisis at the moment.
So CAMHS won't accurately record as they are so far behind / the severity has to be so bad nowadays - you wouldn't really be able to compare to say the figures from the 2000s
As a result, Possibly BEAT would report an increase in cases but more to do with CAMHS failing rather than more people with the disease?