This behavior can be a 'simple' child behavior problem, not symptomatic of any
mentalMental retardation
Mental status tests or emotional disturbance. On the other
handHand or foot spasms
Hand tremor, it can represent an emotional disorder such as Mood Disorder or Disruptive Behavior Disorder. If it is in the realm of a behavior problem and nothing more, it will respond favorably to a systematic program of behavior management. The sort of program I recommend is detailed in books such as Lynn Clark's SOS: Help for Parents. My guess is that you will see a favorable response if you implement such a plan. It is effective in addressing general non-compliance issues with children of any age. The possibility of Mood Disorder increases if there is a family history of such on either your side of the family or your wife's side.
My comments to you Sir are that I feel for you. I first of all think it is mostly Girls...from talking with other parents, and from having two of them myself. I love my girls deeply but sometimes I find myself wondering if I should have even became a parent (thanks to people like COLEP_2003 saying things like they say) I think that it must be me, and that I must be the reason they are the way they are.
I hope you can figure out what to do along with the rest of us, pray, ask God for help, ask friends and family, ask strangers...I am seriously considering medication for my child - I have backed down from it in the past but I can not continue to live my life like this day in and day out, I have done time out it does NOT work, I have done spankings they don't work either, I have taken away toys, I have bribed with rewards for doing good NOTHING WORKS.
If you find an answer please let me know, and DON'T let people like that get you discouraged!
:)