Another factor behind her lying could be that of fear—fear of the consequences or of what others may think if the truth is told. It is only natural that people wish to be liked or accepted by others. This desire, however, can move them to distort the truth, even if only a little, in order … Read more

You need to consider the possibility that your friend is mentally ill.  If she seems to really believe those things, try to contact her family and ask even they have noticed a change in her behavior.  Late teens - early twenties is the prime time of the initial onset of some forms of mental illness.