Noticed an improvement
We bought 3 different types of plug ins as we were getting desperate.
We started with the yellow branded one that stank, but actually worked. We only realised this when it ran out and the behaviour worsened again.
This was the one we whacked in straight after, behaviour calmed again, this time without the honking smell.
I'm not saying these are a miracle worker but they definitely make our household happier.
Our issues were: scratching carpets, scratching at doors, dominance issues.