A newly diagnosed brain disease that is infecting mostly young women may be behind some misdiagnosed psychological disorders, according to some experts.

Anti-NMDA receptor encephalitis, first identified in 2007, is an auto-immune disease that occurs when antibodies turn on the brain and cause it to swell, according to CBS station KYW in Philadelphia. Symptoms can include paranoia, mania, being dazed, personality changes, acting "possessed" and being catatonic, which can lead some medical professionals to diagnose the problem as psychological instead of physical. A study in Innovations in Clinical Neuroscience in 2011 reported that the disease is fatal in 25 percent of the cases. In addition, neurological problems persist in 75 percent of the patients, and relapse occurs 20 percent of the time.

Dr. Souhel Najjar, an associate professor of neurology at NYU medical center and an expert on anti-NMDA receptor encephalitis, told The Guardian that thousands of people have been diagnosed with the unusual disease. However, because it is relatively new and presents itself like other illnesses, he thinks that about 90 percent of those who were suffering from anti-NMDA receptor encephalitis in 2009 went undiagnosed. Because of conditions like this that we are just learning about, Najjar believes that many forms of psychological disorders -- such as types of schizophrenia, bipolar disorder, OCD and depression -- may be due to brain inflammation.

"There could be people in comas right now or people stuck in psych wards that have this disease and aren't being treated properly," Emily Gavigan, who was a sophomore at sophomore at the University of Scranton when she came down with anti-NMDA Receptor Encephalitis, said to KYW.