Schizophrenia is a heterogeneous disorder and among other symptoms, patients have important visual impairments. Visual paradigms are therefore important tools to investigate the mechanisms of schizophrenia. During the last period of the NCCR, we have characterized a very sensitive endophenotype of schizophrenia, based on visual backward masking (VBM). Moreover, we found strongly reduced global field power (GFP) amplitudes to masked stimuli in schizophrenia patients (Plomp et al., 2013). In order to track the progress of the disease and its behavioural and electrophysiological correlates, we have set a longitudinal study with first episode patients (N=20) and have tested them with the masking endophentoype and EEG. We follow up patients every half year and have tested them 3 times up to now (Roinishvili et al., ongoing). The 20 patients tested show clear masking deficits and reduced amplitudes in the EEG compared to controls, but higher amplitudes compared to schizophrenic patients.