From November 2007 to October 2012, patients between 18 and 65 years of age from the outpatient program of “Tor Vergata” University Psychiatry Clinic with a diagnosis of schizophrenia (SCZ) were considered for the study. The inclusion criterion was a stable clinical and pharmacological condition from at least 3 months. The exclusion criteria were history of head trauma, mental retardation, and history in the last 6 months of alcohol, and/or substance abuse. In order to study the effect of illness duration patients were divided in those with short disease duration (SDD, with less than 5 years from the first psychotic episode) and those with long disease duration (LDD, more than 5 years from the first psychotic episode). During the same period, healthy volunteers (HV) of comparable age and socio-economical status without a personal and familiar history of psychiatric disorders were enrolled as controls. The MINI-Plus (Sheehan et al., 1998) was used to confirm the diagnosis of SCZ according to DSM-IV criteria in the clinical sample and the absence of psychiatric diagnosis in the control group. The Positive and Negative Syndrome
