I'm not actually sure if I'm posting in the right section but I'm hoping for some suggestions. As the title suggests, I am concerned about my niece. She is now 13, and has had behavioural issues for as long as I remember. As soon as she hit toddlerhood, she started throwing massive tantrums that grew worse. As she got bigger they became more violent, she would throw things, kick anyone within reach, wreck entire rooms etc. My DSis and BIL have tried every approach over the years, ignoring her tantrums, then as she got older star charts, time out, spending time with her one to one, removing toys/devices etc. Nothing ever made any difference. Academically she has always been ahead for her age and was well behaved at school. Her tantrums lessened as she got past about age 9-10. They were gradually replaced with general surliness, no sense of humour or fun, being very antisocial to the point of rudeness (barely answering when spoken to, hardly ever smiling) since starting high school her school has deteriorated and she now regularly gets detentions for rudeness/answering back. At home she rules the household, they are so worried about upsetting her they let her get her own way all the time, she even tells them they can't go out in the evening and they've cancelled holidays and social plans due to her demanding that they stay at home. It seems clear to me and has done for a long time that she is a very unhappy child, but they have not sought help beyond seeing a primary school counsellor for a while. Anyone experienced this kind of behaviour/personality type? I wonder if she has some kind of mental health issue or if she is on the autistic spectrum but I don't know enough about it.