I have battled with my own anxiety and depression all my life, but they are quite well under (medical) control these days, so it is still rather my own experience informing how I am trying to help my kids.
However, I have recently been coming to terms with the fact that I may be a quite bad case of ADHD (inattentive) it would explain a lot of my academic and professional struggles. All of my life, I have been completely unable to sit still/listen/focus/apply myself when mentally understimulated. I either start wriggling, running around (I once got thrown out of the law library!) or go off into a daydream until I fall asleep). Exam conditions, deadlines etc usually help, so on the outside it does not appear to have hurt my academic and professional achievement, but I know better. It's one of the reasons I dropped my PhD thesis. And no one suspects just how little time I ever spent actually focusing on studying, or on doing my job. I sometimes wonder what if but I do think it's too late to make much difference.