ERVW-1 and psychotic disorder: Moreover, several clinical studies reported that the expression of human ERV-W, Env (envelope), and Gag (capsid/matrix) in the brain, CSF, and serum of patients with psychotic disorders [12–17], suggesting that copies retaining potential to express retroviral proteins or particles could be used to stratify patients with psychotic disorders into subgroups with differing inflammatory and clinical profiles [18, 19].