Spoecificity and effects of treatment on SE modulation in schizophrenia

We assessed SE modulation of EEG during a P300 task in 79 schizophrenia patients (of them, 31 first episodes (FE)), 29 bipolar patients and 48 healthy controls. In a subsample, structural network connectivity parameters were calculated using diffusion tensor imaging. Significant SE modulation deficits were found in chronic and FE schizophrenia and bipolar patients. These deficits were unrelated to treatment doses. SE modulation values did not differ between patients receiving or not antipsychotics, lithium, benzodiazepines or antidepressants. Structural connectivity values were unrelated to SE modulation. In schizophrenia, SE modulation was inversely related to negative symptoms and directly to verbal memory. In conclusion, SE modulation with cognition is decreased in schizophrenia and bipolar disorder. This decrease was not an effect of psychopharmacological treatment or structural connectivity and might reflect a deficit in synchronization of neural assemblies underlying cognitive activity in major psychoses.