My 15 yr old DD spends virtually every waking moment glued to her smartphone screen (fortunately, she isn't allowed a mobile at school, so there are some enforced breaks during term time). When I threaten to take it off her, she goes ballistic and her personality changes completely. She behaves like someone addicted to a hard drug, wide eyed and manic just at the very thought of her phone being taken away for a short time (I only suggested that she hand her phone over to me when she goes to bed). Her reaction and bad temper really scares me. Thing is, she is somehow managing to keep up with her school work and, at the moment, is predicted to get A*s in all subjects except one. She says that there is no reason to take her phone away as that would be punishing her when she is actually doing really well. She has got two GCSEs coming up this year and the rest next year. I don't know what to do....should I restrict her use or do you think that if she is doing OK I shouldn't worry? I should add that she doesn't get pocket money and she doesn't go out very often (never at night). Apart from the phone and the usual teenage tantrums and door slamming, she is no trouble. I'm just worried that she could throw everything away just for the sake of chatting or whatever they do on Instagram.