HEADBUTTING

[scoot]

MY 12MTH DS KEEPS HITTING HIMSELF OVER THE HEAD AND HEADBUTTING. HE WILL HIT HIMSELF WITH ANYTHING HE HAS HOLD OF, OR JUST SLAP HIMSELF. HE WILL HEADBUTT FURNITURE, WALLS AND DOORS. IF THERE IS NOTHING IN DISTANCE HE WILL JUST BEND OVER AND BUTT THE FLOOR.
I DONT KNOW WHAT TO DO ABOUT IT. PEOPLE LAUGH WITH AMAZEMENT WHEN HE DOES THIS. I FIND IT QUITE DISTRESSING. ANY ADVICE?

Does he do it only when he is upset or all the time?

he does it all the time, when he is playing, just walking around. but he does do it more when he is upset or angry. i can't find a reason its constant