In brain samples, cerebrospinal fluid and blood of patients with schizophrenia and schizoaffective disorders elevated levels of transcripts and/or proteins from at least three HERV groups, HERV-W, ERV9 and HERV-K(HML-2), have been repeatedly detected [20], [21], [22], [23], [24], [25], [26]. Here, ERVW-1 is linked to schizophrenia.