Maes M, Schotte C, Maes L, Cosyns P
Dept. of Biological Psychiatry, University Hospital of Antwerp, UZA, Edegam, Belgium.
Psychiatry Res. 1990 Oct;34(1):43-57. doi: 10.1016/0165-1781(90)90057-c.
This study examines whether the differences in the cluster-analytically generated classes--nonvital versus vital depression--are dimensional (quantitative) rather than categorical (qualitative). To this end, we used various pattern-recognition methods based on principal component analysis (PCA), e.g., display methods (PC plotting), eigenanalysis, and SIMCA (statistical isolinear multiple components analyses). We found several arguments supporting the dimensional hypothesis that the nonvital and vital classes constitute relevant stages (continuous categories) in the continuum of illness-severity. Nevertheless, we found some arguments supporting the categorical hypothesis that the cluster-analytically generated classes are qualitatively different with reference to the similarity of the vital symptoms. Our findings suggest that a nosological or categorical classification is possible from the moment that one component (i.e., the vital component) is quantitatively prominent to the extent that it has become qualitative. As the overall severity of illness increases, vital symptoms emerge which, grouped together, shape a new symptom profile (i.e., vital depression). Thus, our results favor the hypothesis that there are simultaneous quantitative (dimensional: overall severity of illness) and qualitative (categorical: vital symptoms) differences between the nonvital and vital depression groups.
本研究探讨了聚类分析得出的类别（非重症与重症抑郁症）差异是维度性（定量）的而非类别性（定性）的。为此，我们使用了基于主成分分析（PCA）的各种模式识别方法，例如展示方法（主成分绘图）、特征分析和SIMCA（统计等线性多成分分析）。我们发现了几个论据支持维度假说，即非重症和重症类别构成疾病严重程度连续统中的相关阶段（连续类别）。然而，我们也发现了一些论据支持类别假说，即聚类分析得出的类别在重要症状的相似性方面存在质的差异。我们的研究结果表明，从一个成分（即重要成分）在数量上突出到一定程度以至于具有质性特征的那一刻起，进行疾病分类学或类别分类是可能的。随着疾病总体严重程度的增加，重要症状出现，这些症状聚集在一起形成了一种新的症状特征（即重症抑郁症）。因此，我们的结果支持这样一种假说，即非重症和重症抑郁症组之间同时存在数量（维度：疾病总体严重程度）和质性（类别：重要症状）差异。
