de Wilde O M, Bour L J, Dingemans P M, Koelman J H T M, Linszen D H
Department of Psychiatry, Academic Medical Centre, University of Amsterdam, the Netherlands.
Schizophr Res. 2007 Dec;97(1-3):137-51. doi: 10.1016/j.schres.2007.04.028. Epub 2007 Jun 29.
To determine whether patients with schizophrenia as well as their relatives show deficits in sensory gating reflected by an abnormal P50 ratio and to quantify the differences from controls.
A systematic search on articles published between 1982 and 2006 was conducted. 28 patient studies that were suitable for analysis including 891 patients and 686 controls were retrieved. Six studies on P50 of relatives of schizophrenic patients were identified, including 317 relatives and 294 controls.
In the patient studies we found an P50 effect size of 1.28 (SD=0.72). We confirmed high variability in outcomes across studies. Almost half of the studies included where published by one laboratory of the University of Colorado and these results differed significantly from the results found in studies performed in other laboratories. We found correlations between effect size outcome and sound intensity, filter settings and subjects' position which could be explained by differences between the Colorado laboratory and the other groups. In the relative studies we found a mean P50 effect size of 0.85 (+/-0.42).
The differences in methodology and lack of reported demographics and methodology including raters blinding in some studies makes it hard to compare results across studies and to evaluate the validity and reliability of P50 as a candidate endophenotype for schizophrenia. There are large differences in outcomes from Colorado studies and non-Colorado studies. In contrast to the Colorado studies in the non-Colorado studies P50 suppression would not qualify as an endophenotype for schizophrenia. These differences might be explained by the differences in methodology e.g. lower levels of sound intensity, differences in filter settings and subjects' position. Finally we make some recommendations for future research based on the outcomes of this meta-analysis.
确定精神分裂症患者及其亲属是否存在感觉门控缺陷，该缺陷由异常的P50比率反映，并量化与对照组的差异。
对1982年至2006年间发表的文章进行系统检索。检索到28项适合分析的患者研究，包括891名患者和686名对照。确定了6项关于精神分裂症患者亲属P50的研究，包括317名亲属和294名对照。
在患者研究中，我们发现P50效应量为1.28（标准差=0.72）。我们证实了各研究结果的高度变异性。几乎一半的纳入研究由科罗拉多大学的一个实验室发表，这些结果与其他实验室进行的研究结果有显著差异。我们发现效应量结果与声音强度、滤波器设置和受试者位置之间存在相关性，这可以用科罗拉多实验室与其他组之间的差异来解释。在亲属研究中，我们发现平均P50效应量为0.85（±0.42）。
方法学上的差异以及一些研究中未报告人口统计学和方法学（包括评分者盲法），使得难以比较各研究结果，也难以评估P50作为精神分裂症候选内表型的有效性和可靠性。科罗拉多研究与非科罗拉多研究的结果存在很大差异。与科罗拉多研究不同，在非科罗拉多研究中，P50抑制不能作为精神分裂症的内表型。这些差异可能由方法学差异解释，例如较低的声音强度水平、滤波器设置差异和受试者位置差异。最后，我们根据这项荟萃分析的结果对未来研究提出了一些建议。
