I almost forgot to mention that people can not only get a sadistic personality disorder from bullying but they can also get it from an abusive parents or that they are not in a good relationship with somebody or that this person felt betrayed and break up with somebody which also makes them feel sad and lonely so that basically it.
But there is a treatment that can work on the sadistic personality disorder such as behavior therapy, and hypnosis which should work by the way.
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