Graeff Philipp, Stacheneder Regina, Alt Laura, Ruscheweyh Ruth
Graduate School of Systemic Neuroscience, Ludwig-Maximilians-University Munich, 82152 Planegg, Germany.
RTG 2175 "Perception in Context and Its Neural Basis", Ludwig-Maximilians-University Munich, 82152 Planegg, Germany.
Brain Sci. 2022 May 10;12(5):623. doi: 10.3390/brainsci12050623.
Conditioned pain modulation (CPM) describes the decrease in pain perception of a test stimulus (TS) when presented together with a heterotopic painful conditioning stimulus (CS). Inter-individual differences in CPM are large and have been suggested to reflect differences in endogenous pain modulation. In a previous analysis, we demonstrated that in young, healthy participants, inter-individual differences account for about one-third of CPM variance, with age and sex together explaining only 1%. Here, we investigated if psychological factors explain significant amounts of inter-individual variance in CPM. Using the same dataset as before, we performed both cross-sectional (n = 126) and repeated measures (n = 52, 118 observations) analysis and the corresponding variance decompositions, using results of psychological questionnaires assessing depression, trait anxiety and pain catastrophizing. Psychological factors did not significantly predict CPM magnitude, neither directly nor when interactions with the CPM paradigm were assessed; however, the interaction between depression and the paradigm approached significance. Variance decomposition showed that the interaction between depression and the CPM paradigm explained an appreciable amount of variance (3.0%), but this proportion seems small when compared to the residual inter-individual differences (35.4%). The main effects of the psychological factors and the interactions of anxiety or catastrophizing with the CPM paradigm are explained at <0.1% each. These results show that the contribution of psychological factors to inter-individual CPM differences in healthy participants is limited and that the large inter-individual variability in the CPM effect remains largely unexplained.
条件性疼痛调制（CPM）是指当一个测试刺激（TS）与一个异位疼痛条件刺激（CS）同时呈现时，疼痛感知的降低。CPM的个体间差异很大，有人认为这反映了内源性疼痛调制的差异。在之前的一项分析中，我们证明在年轻健康的参与者中，个体间差异约占CPM方差的三分之一，年龄和性别共同解释的方差仅为1%。在此，我们研究了心理因素是否能解释CPM中显著的个体间方差。使用与之前相同的数据集，我们进行了横断面分析（n = 126）和重复测量分析（n = 52，118次观察）以及相应的方差分解，使用了评估抑郁、特质焦虑和疼痛灾难化的心理问卷结果。心理因素无论是直接还是在评估与CPM范式的相互作用时，都没有显著预测CPM的大小；然而，抑郁与范式之间的相互作用接近显著水平。方差分解表明，抑郁与CPM范式之间的相互作用解释了相当数量的方差（3.0%），但与个体间的残余差异（35.4%）相比，这个比例似乎较小。心理因素的主效应以及焦虑或灾难化与CPM范式的相互作用各自解释的方差均<0.1%。这些结果表明，心理因素对健康参与者个体间CPM差异的贡献有限，CPM效应中个体间的巨大变异性在很大程度上仍无法解释。
