The aim of this study was to identify functional, including intercorrelated, deficits in the domains of attention, memory, and information processing among first-episode schizophrenia patients without auditory hallucinations. Such deficits can be objectively assessed using auditory evoked potential measurements. The study sample consisted of two groups: the first included fifty-eight schizophrenia patients whose first episode did not include auditory hallucinations, from the outpatient psychiatric and neurology clinics of Zagazig University Hospitals. The second group included 53 participants randomly selected from visitors to Zagazig University Hospitals. Patients underwent a structured clinical diagnostic interview from the DSM-IV, an auditory mismatch negativity (MMN) test, and their P300 wave was measured before and after treatment. The degree of disability was also assessed, and its correlation with auditory processing function was determined. Our study showed no statistically significant difference regarding the relationship between MMN measurements and any noticeable effect of atypical antipsychotics. The P300 wave showed delayed latency and a smaller amplitude before treatment, which was significantly enhanced after treatment. A statistically significant correlation was found between the degree of disability, auditory mismatch negativity, and P300 measurements both before and after treatment. The study concluded that attention-dependent processes, as manifested in P300 measurements, are indeed impaired during the first episode of schizophrenia and can be improved with atypical antipsychotic medication.