“…Several studies have explored socio-demographic characteristics Messias et al, 2004), risk factors (Kirkpatrick et al, 2000a), clinical outcome (Carpenter, 1994;Tek et al, 2001), response to treatment (Kirkpatrick et al, 2000b) and neurobiological features Ross et al, 1997;Waltrip et al, 1997;Hong et al, 2005) associated with SZD. Some studies have demonstrated double dissociations (SZD patients impaired on measure A but not B; SZND patients impaired on measure B but not A) in metabolic measures (Garcia-Rizo et al, 2012), season of birth (Messias et al, 2004), and electrophysiological variables (Mucci et al, 2007). These studies are consistent with the concept that SDZ is a separate disorder within the syndrome of schizophrenia.…”