Many children diagnosed with ADHD have symptoms that are so different that they deserve a completely different diagnosis, called Sluggish Cognitive Tempo (SCT). People with SCT are more prone to anxiety and depression.

http://sciencenordic.com/adhd-diagnosis-not-good-fit-daydreamers

https://forskning.no/psykologi/dagdrommere-passer-ikke-inn-i-adhd-diagnosen/1268388