Children often times can hold it together during a school day, then when they get home in the comfort of those they love, let loose.
Has your daughter always been a bit difficult, or is this behavior somewhat new? My youngest daughter was always challenging, but my 3rd daughter had a shift once she hit puberty. Estrogen dramatically increases during puberty and may contribute to depression / mood issues. Here is a good link about teens and depression: http://www.helpguide.org/articles/depression/teen-depression-signs-help.htm
You may want to have an evaluation done by a professional if your home-life has turned into a battle ground, and you guys are having a hard time 'enjoying' your daughter.
I understand how hard this is, and believe me, you're not alone. Take care! -KathleenView Thread
My youngest daughter had emotional melt-downs since age 2, so I completely understand where you are coming from.
Melt-downs can "look" like they come out of nowhere, but I guarantee, the child is having them for a reason - a reason you don't yet see or understand.
Some children are just more sensitive - plain and simple. They can have a melt-down when their over-tired, hungry, don't get their way, are internally upset over something that happened at school or home. Lots of reasons.
Children such as these do better with Positive Discipline techniques - and I would encourage you to seek these out. Spanking a child will not help, and I guarantee it will make it worse. I understand how frustrating it is for a parent to not stop the behavior - but a far better idea is to ignore it. Ignoring it, gives the tantrum no power. Stay calm, talk in a low voice, go about your activity and ignore her completely until she stops.
When a young child is acting out such as you describe, I think getting to the root of his behavior is most important now.
I would find a really good, smart Child Psychologist to evaluate your son. A good psychologist will do an intake with both parents, send forms to school for the teacher to fill out, and spend several visits alone with the child before coming up with a treatment recommendation.