Sadistic (definition): deriving pleasure from inflicting pain, suffering, or humiliation on others.
I think I may have some insight. I have always had a very active mind with various competing ideas popping up all of the time. I have always been this way so I just assumed that everyone was like this. Except that since becoming an empath I now understand that there are a lot of things going on in my mind including that some of the thoughts are not my own.
I hate to use the term that I "hear voices". Because non-empaths start to think you're on the train to crazy town. But I hear voices in my mind that come through as my thought voice that I now understand are messages from various things that I pick up. Sometimes these voices give me creative ideas or helpful ideas to act on. And other times I hear compassionate thoughts directing me to help someone, or give someone a hug. And then every once in a while I will get a really ugly or low energy thought that is very blasphemous or inappropriate.
I wonder if you are like me and are picking up "sadistic" from a low energy spirit? I find that spirits whisper and put thoughts in my mind that usually come through as a single word or a brief sentence. As a pure guess here, you may be getting that from a spirit that was sadistic in life. And that is the label they carry in guilt or anger that keeps them tied to the earth plane.