paralyzed = losing courage?

or does it mean " affected with paralysis?"

Context:

The stress of combat left some soldiers paralyzed, the testimony shows. Troops, traumatized by the rising violence and feeling constantly under siege, grew increasingly twitchy, killing more and more civilians in accidental encounters. Others became so desensitized and inured to the killing that they fired on Iraqi civilians deliberately while their fellow soldiers snapped pictures, and were court-martialed. The bodies piled up at a time when the war had gone horribly wrong.

More:

http://www.nytimes.com/2011/12/15/world/middleeast/united-states-marines-haditha-interviews-found-in-iraq-junkyard.html?_r=1&hp