What Causes Persistent Headaches And Depression After Giving Birth?

Since my daughter gave birth she has been getting worse, it s been 8years now, and she always seems depressed, sick, can t hold a job, complains the top of her head hurts, like something s in there, thought it was a tumor, had a scan done at the hospital, they said she s fine and sent her home. She sleeps all the time and says she s not feeling right, losing her memories, anxiety when driving, and now hearing voices and having demonic dreams. Can post partum last this long, or is she just going crazy, or could it be depression or schizophrenia. Where she she go? She wants to get better, but every doctor she s gone to in Southern California, just says nothing s wrong, no rumors, and sends her home?