neuro-degenerative effect of antipsychotics. Moreover, early stages of the schizophrenic disease have different clinical and pathophysiological features from those seen in patients with long disease duration (van Os and Kapur, 2009). Furthermore, positive and negative symptoms associated with acute Ketamine administration in HV are associated with hyperconnectivity (Driesen et al., 2013); this finding has strong analogy with functional changes observed in individuals at high risk for schizophrenia and in the early stages of the disease (Anticevic et al., 2015). The glutamatergic-dependent hyperconnectivity appears to be specific for the early phases of schizophrenia and not a feature present in chronic patients.
