It’s possible that your sister is experiencing a break with reality. She believes in ideas that are not real. She seems to believe that she’s being attacked by demons. By definition, this would be a delusion. A delusion is a belief in something despite there being evidence to the contrary.
The event that you described is particularly concerning because it led to her hurting you and herself. She attacked you because of fear. She may have hurt herself because she was attempting to fight off the demon that she thought was attacking her.
You are correct to be concerned. Her psychiatrist believes she has an anxiety disorder but the symptom you described may be a delusion, which is associated with psychosis. Only a thorough evaluation could properly determine what is wrong with your sister.
My recommendation is to report this incident to her psychiatrist. If he is unconcerned with the information that you have shared, then consider consulting a new psychiatrist. Getting a second opinion is always a wise idea.
In the meantime, try to keep your sister feeling safe and calm. Always try to reduce the stress levels in the home as much as possible. Stress is known to exacerbate both symptoms of psychosis and anxiety. Please take care.
Dr. Kristina Randle