Murderous Tendencies

Either A you suffering from underlying trauma or B you're just crazy but you have the tendency to attack others and I don't mean just down them, if left alone you will kill the npc or player while in this state. And the two solutions is either to be knocked out or, fail the skill roll.

You obtain a skill called Murderous Intent 

It scales off wisdom and the least you can have it at is semi- Proficient, the DC is 15 I you roll under 15 you are stable for the moment. 

The Dm can also decree when your needed to roll it with advantage or disadvantage. 

This is considered a flaw feat you may +2 to one stat or +1 to two stats.