How to deal with a sociopath boss?

Two thoughts here:

1. Maybe it is the case you are doing better when your boss thinks so. Pay attention to their comments. In fact, document them. Doing this will allow you to see if you are doing better when your boss says so or not and to track your boss's attitude toward your work as its quality varies. Which leads me to my next potential thought...
2. Your boss hates you and you can show it. If this is the case, I think that it might be time for a change. Lay low and begin recruiting, for at least looking for other internal positions. 

If you work with your boss a lot, and feel comfortable enough, it might be worth telling them that you've noticed a disruption in your workflow, and perhaps talk about ways to best navigate feedback with your boss. If you do not think this is a conversation you can realistically have though, just lay low