Patients with schizophrenia suffer from cognitive deficits in seven domains in addition to social cognition. P300 latency and amplitude have been linked in these patients to the basic cognitive deficits.

Comparing patients suffering from schizophrenia with matched healthy subjects as regards auditory event related potential tests as measured by P300.

Fifty-two subjects were divided into 2 groups: group (A): 27 patients with schizophrenia according to the diagnostic and statistical manual of mental disorders-text revised (DSM-IV TR). Those with current substance use, psychiatric disorders or organic disorders were excluded. Group (B): 25 healthy control subjects with negative history of substance and psychiatric disorders. Patients were assessed using Positive and Negative Symptom Scale (PANSS) for severity of psychotic symptoms, Addenbrook's Cognitive Examination Revised (ACE-R) for basic cognitive, reading the mind in the eye test for social cognition, P300 and electro-encephalography (EEG)

The two groups were different significantly in ACE total and its subtests measuring attention-orientation, memory, language, visuospatial and reading the mind in the eye test for social cognition scores with patients showing lower scores (P = 0.000, 0.012, 0.000, 0.038, 0.041 and 0.001 respectively). Control group had higher amplitude of P300 and shorter latency than patients (P = 0.003 and 0.005 respectively). P300 amplitude correlated positively with visuospatial memory (P = 0.015). PANSS general pathology scale correlated positively with duration of untreated psychosis (P = 0.029) and with fluency (P = 0.047).

Patients with schizophrenia differ from controls in P300.

The authors have not supplied their declaration of competing interest.