Combat Paralysis is one of Fallout GURPS disadvantages. See: Fallout GURPS.
This is the opposite of Combat Reflexes; you tend to "freeze up" in a combat situation. It's not worth more as a disadvantage, simply because most people who have it find out at an early age . . . and then steer away from careers in which they might face danger. This is not the same as cowardice; you don't have to roleplay fear. Your mind may be brave, but your body betrays you. In any situation in which personal harm seems imminent, roll against your HT. You do not roll until the instant in which you first need to fight, run, pull the trigger, etc. A successful roll means you can act normally. A failed roll means you are frozen, as though you'd been taken by surprise (see p. B106). You must roll every turn, at +1 to your effective HT each turn, to break the freeze. A quick slap from a friend will also give +1 to your cumulative chance of coming out of it. Once you unfreeze, you will not freeze again until the fight is over or you reach safety. Then you will again be susceptible to freezing, the next time danger threatens.”— Steve Jackson Games GURPS sources
With the abandonment of GURPS, Combat Paralysis was removed from the game