Department of Psychiatry, Tokyo Women's Medical University, Tokyo, Japan.
BMC Psychiatry. 2010 Dec 7;10:105. doi: 10.1186/1471-244X-10-105.
Although the Brief Psychiatric Rating Scale (BPRS) is widely used for evaluating patients with schizophrenia, it has limited value in estimating the clinical weight of individual symptoms. The aim of this study was 4-fold: 1) to investigate the relationship of the BPRS to the Clinical Global Impression-Schizophrenia Scale (CGI-SCH), 2) to express this relationship in mathematical form, 3) to seek significant symptoms, and 4) to consider a possible modified BPRS subscale.
We evaluated 150 schizophrenia patients using the BPRS and the CGI-SCH, then examined the scatter plot distribution of the two scales and expressed it in a mathematical equation. Next, backward stepwise regression was performed to select BPRS items that were highly associated with the CGI-SCH. Multivariate regression was conducted to allocate marks to individual items, proportional to their respective magnitude. We assessed the influence of modifications to the BPRS in terms of Pearson's r correlation coefficient and r-squared to evaluate the relationship between the two scales. Utilizing symptom weighting, we assumed a possible BPRS subscale.
By plotting the scores for the two scales, a logarithmic curve was obtained. By performing a logarithmic transformation of the BPRS total score, the curve was modified to a linear distribution, described by [CGI-SCH] = 7.1497 × log10[18-item BPRS] - 6.7705 (p < 0.001). Pearson's r for the relationship between the scales was 0.7926 and r-squared was 0.7560 (both p < 0.001). Applying backward stepwise regression using small sets of items, eight symptoms were positively correlated with the CGI-SCH (p < 0.005) and the subset gave Pearson's r of 0.8185 and r-squared of 0.7198. Further selection at the multivariate regression yielded Pearson's r of 0.8315 and r-squared of 0.7036. Then, modification of point allocation provided Pearson's r of 0.8339 and r-squared of 0.7036 (all these p < 0.001). A possible modified BPRS subscale, "the modified seven-item BPRS", was designed.
Limited within our data, a logarithmic relationship was assumed between the two scales, and not only individual items of the BPRS but also their weightings were considered important for a linear relationship and improvement of the BPRS for evaluating schizophrenia.
虽然简明精神病评定量表（BPRS）被广泛用于评估精神分裂症患者，但它在估计个体症状的临床权重方面的价值有限。本研究的目的有四：1）探讨 BPRS 与临床总体印象-精神分裂症量表（CGI-SCH）的关系；2）用数学形式表达这种关系；3）寻找显著症状；4）考虑可能的改良 BPRS 亚量表。
我们用 BPRS 和 CGI-SCH 对 150 例精神分裂症患者进行评估，然后考察两量表的散点图分布，并以数学方程表示。接着，采用向后逐步回归选择与 CGI-SCH 高度相关的 BPRS 项目。采用多元回归为各项目分配分值，与各自的权重成正比。我们评估了对 BPRS 的修改对 Pearson r 相关系数和 r 平方的影响，以评估两量表之间的关系。利用症状加权，我们假设了一个可能的 BPRS 亚量表。
通过绘制两量表的得分，得到一条对数曲线。对 BPRS 总分进行对数转换后，曲线被修改为线性分布，可由[CGI-SCH]=7.1497×log10[18 项 BPRS]-6.7705（p<0.001）表示。两量表之间的 Pearson r 为 0.7926，r 平方为 0.7560（均 p<0.001）。采用小数据集的向后逐步回归，8 个症状与 CGI-SCH 呈正相关（p<0.005），该亚量表的 Pearson r 为 0.8185，r 平方为 0.7198。进一步在多元回归中选择，得到 Pearson r 为 0.8315，r 平方为 0.7036。然后，对分值分配进行修改，得到 Pearson r 为 0.8339，r 平方为 0.7036（均 p<0.001）。设计了一个可能的改良 BPRS 亚量表“改良的七项 BPRS”。
在我们的数据范围内，假设两量表之间存在对数关系，不仅 BPRS 的各个项目，而且它们的权重对于线性关系和改良 BPRS 评估精神分裂症都很重要。
