My first thought is that the parent or parents need to do something to control their kid. I don't advocate any method of punishment over the other, you can throw as many studies at me as you like saying so and so works better than this and that, but each individual is going to react to different punishments in different ways. A parent should experiment with different styles and use whichever works best for their individual child, and as long as it's humane and works, it's alright by me. But in my personal opinion, jumping straight to physical violence shouldn't be the first answer, it should be a last resort. It may work for some kids, but you still run the risk of them growing up with unresolved emotional issues and becoming resentful of you. Children shouldn't be the ones who control their parents, but taking into account all of the possible gains and losses of different scenarios is never a bad idea. (By the way, if someone is seriously still throwing tantrums at the age of fifteen, unless they have a disability of some sort there is a major problem there.)