Hallucinations of blood on hands?

My girlfriend recently has been hearing voices. In addition to that, she just had a hallucination of blood on her hands. She said she was filling up a glass of water and she looked at her hand and saw and felt blood. She blinked and it was gone. She's also seen dark figures through our glass door outside in midday. She's had a very traumatizing past, she doesn't drink, she isn't on any medication. She gets a lot of restful sleep. She also suffers from depression and has suicidal thoughts. Why is she having these hallucinations and how can they be stopped?