Objective To explore the relationship between the cognitive disorders in the first episode of schizophrenia and P300 components.Methods P300 components were measured by using an auditory oddball paradigm with a Denmark KeyPoint Evoked Potentials instrument in 60 cases of schizophrenia and 3 cases of schizophreniform disorder,whose psychopathological status was assessed with the Positive and Negative Syndrome Scale(PANSS).Forty healthy subjects were used as control.Results The principal component analysis of the PANSS items revealed five factors:cognitive disorder,negative symptoms,depressive disorder,hostility/excitement and delusion/hallucination.The patients had lower amplitude of P300 at Fz,Cz,Pz,T3 and T4 than the normal controls(P