L1CAM and psychotic disorder: To our knowledge, there are only four published studies on psychosis and EVs: one based on brain biopsies (Banigan et al., 2013), a case report involving cerebrospinal fluid (CSF) analysis (Mobarrez et al., 2013), and two studies showing altered insulin signaling in L1 cell adhesion molecule (L1CAM) positive EVs in patients with schizophrenia (Kapogiannis et al., 2019a; Wijtenburg et al., 2019).