P300 waveform and dopamine transporter availability: a controlled EEG and SPECT study in medication-naive patients with schizophrenia and a meta-analysis.
BACKGROUND
Reduced P300 event-related potential (ERP) amplitude and latency prolongation have been reported in patients with schizophrenia compared to healthy controls. However, the influence of antipsychotics (and dopamine) on ERP measures are poorly understood and medication confounding remains a possibility.


METHODS
We explored ERP differences between 36 drug-naive patients with schizophrenia and 138 healthy controls and examined whether P300 performance was related to dopamine transporter (DAT) availability, both without the confounding effects of medication. We also conducted a random effects meta-analysis of the available literature, synthesizing the results of three comparable published articles and our local study.


RESULTS
No overall significant difference was found in mean P300 ERP between patients and controls in latency or in amplitude. There was a significant gender effect, with females showing greater P300 amplitude than males. A difference between patients and controls in P300 latency was evident with ageing, with latency increasing faster in patients. No effect of DAT availability on P300 latency or amplitude was detected. The meta-analysis computed the latency pooled standardized effect size (PSES; Cohen's d) of -0.13 and the amplitude PSES (Cohen's d) of 0.48, with patients showing a significant reduction in amplitude.


CONCLUSIONS
Our findings suggest the P300 ERP is not altered in the early stages of schizophrenia before medication is introduced, and the DAT availability does not influence the P300 ERP amplitude or latency. P300 ERP amplitude reduction could be an indicator of the progression of illness and chronicity.
Department of Psychiatry,National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University,Tainan,Taiwan.
K C
KC
Chen
Department of Psychiatry,National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University,Tainan,Taiwan.
I H
IH
Lee
Department of Psychiatry,National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University,Tainan,Taiwan.
Y K
YK
Yang
Department of Biostatistics, Institute of Psychiatry,King's College London,UK.
S
S
Landau
Department of Psychiatry,National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University,Tainan,Taiwan.
W H
WH
Chang
Department of Psychiatry,National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University,Tainan,Taiwan.
P S
PS
Chen
Department of Psychiatry,National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University,Tainan,Taiwan.
R B
RB
Lu
Department of Psychosis Studies, Institute of Psychiatry,King's College London,UK.
A S
AS
David
Department of Psychosis Studies, Institute of Psychiatry,King's College London,UK.
E
E
Bramon
D000293:Adolescent; D000328:Adult; D000375:Aging / Q000378:metabolism / Q000502:physiology; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D004569:Electroencephalography; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012559:Schizophrenia / Q000378:metabolism* / Q000503:physiopathology*; D012737:Sex Factors; D015899:Tomography, Emission-Computed, Single-Photon; D055815:Young Adult
D050483:Dopamine Plasma Membrane Transport Proteins