Bipolar Disorder Causes?

Hi there! I am here for my daughter. She is 19 years old and she is suffering from schizophrenia and bipolar disorder syndrome. She was not like this one year ago. She was a very quite child and emotionally sound as well. But now she has this unreasonable anger and anxiety in her for no reason. I want to know about the bipolar disorder causes from people so that she can get the proper treatment.