Related Experiment Video
Updated: Oct 20, 2026
Assessment and Communication for People with Disorders of Consciousness
Published on: August 1, 2017
P300 amplitude is related to clinical state in severely and moderately ill patients with schizophrenia
J M Ford1, D H Mathalon, L Marsh
1Department of Psychiatry & Behavioral Sciences, Stanford University School of Medicine, CA 94305-5550, USA.
Background:
Relationships between illness severity and neurobiologic abnormalities in schizophrenia were studied in subpopulations varying in clinical severity.
Methods:
Auditory ERPs were collected from 28 severely ill, chronically hospitalized schizophrenic men from a state hospital; 29 moderately ill inpatient and outpatient schizophrenic men from a veterans hospital; and 30 healthy male subjects from the community as controls. Clinical symptoms were evaluated in patients using the Brief Psychiatric Rating Scale (BPRS).
Results:
Both schizophrenic patient groups had smaller P300 amplitude than the control subjects. Severely ill patients had smaller P300s than moderately ill patients and scored higher on three BPRS factor scores as well as BPRS Total. Among severely ill patients, P300 amplitude was unrelated to clinical symptoms. Among moderately ill patients, P300 was related to Withdrawal/Retardation, Anxiety/Depression, and BPRS Total. After combining patients, Thinking Disturbance emerged as an additional correlate of P300. Group differences in P300 could not be accounted for by group differences in symptom severity using analysis of covariance.
Conclusions:
Reduced P300 amplitude marks the diagnosis of schizophrenia, but also reflects individual differences in severity, including positive symptoms. Previous failures to find relationships between positive symptoms and P300 may have been due to a restricted range of clinical severity.
Insights
Reduced P300 amplitude in schizophrenia diagnosis is linked to illness severity and positive symptoms. This neurobiologic abnormality reflects individual differences in schizophrenia, even positive symptoms.
Area of Science:
- Neuroscience
- Psychiatry
- Clinical Psychology
Background:
- Schizophrenia is associated with neurobiologic abnormalities.
- Illness severity in schizophrenia may correlate with these abnormalities.
Purpose of the Study:
- To investigate the relationship between illness severity and neurobiologic abnormalities in schizophrenia.
- To examine auditory event-related potentials (ERPs) in relation to clinical symptoms.
Main Methods:
- Auditory ERPs were recorded from 28 severely ill, 29 moderately ill schizophrenic men, and 30 healthy controls.
- Clinical symptoms were assessed using the Brief Psychiatric Rating Scale (BPRS).
Main Results:
- Both schizophrenic groups exhibited smaller P300 amplitude compared to controls.
- Severely ill patients had smaller P300 amplitudes than moderately ill patients.
- P300 amplitude correlated with specific BPRS factors in moderately ill patients and overall severity when groups were combined.
Conclusions:
- Reduced P300 amplitude is a biomarker for schizophrenia diagnosis.
- P300 amplitude reflects individual differences in schizophrenia severity, including positive symptoms.
- Previous studies may have underestimated the P300-symptom relationship due to limited clinical severity ranges.
Related Concept Videos
01:26Psychosis: Goals of Pharmacotherapy
01:30Positive Symptoms of Schizophrenia: Hallucinations and Delusions
Thought Disorders
Disorganized and unusual thought processes mark thought disorders in schizophrenia. One key feature is disorganized speech, where an individual's conversation includes loosely...
01:17Schizophrenia
01:30Negative and Cognitive Symptoms of Schizophrenia
Negative Symptoms
Negative symptoms of schizophrenia manifest as deficits in normal emotional and behavioral functioning, profoundly impacting daily life. Individuals with schizophrenia often display a flat affect, characterized by a near-total absence of emotional expression,...