I don't agree, lot's of kids go through stages and there never always a cause of it, it's part of pushing boundries imo, learning etc

Don't always go looking for an underlying issue as there may not be one, physco analysing everything a child does isn't healthy for them or the parent.

If it doesn't work try something else, most kids arent damion no matter how much we think they are.

And if I can only offer one tip that works for me, do not shout, I try to never shout, as said my daughters 11 and sons 5, both of them have only ever heard me shout a couple of times cause we all have done it at some point when returning home from work tired etc but it just isnt worth it, doesnt get you anywhere.