OBJECTIVE Depressive symptom dynamics, including change trajectories and symptom variability, have been related to therapy outcomes. However, such dynamics have often been examined separately and related to outcomes of interest using two-step analyses, which are characterized by several limitations. Here, we show how to overcome these limitations using location-scale models in a dynamic structural equation modeling framework. METHOD We introduce location-scale modeling in an accessible manner to pave the way for its use in research integrating within-person dynamics and intervention-related change in psychopathology, and we illustrate this modeling approach in a large-scale internet-based intervention for depression (N = 1,656). Using eight data points sampled across about 8 weeks, we predicted improvement across the intervention (50% symptom reduction) as a function of early change and symptom variability. RESULTS Early symptom change was associated with a more likely improvement across therapy. Variability of symptoms beyond change trajectories during the intervention was associated with less likely improvement. CONCLUSIONS Location-scale models, and dynamic structural equation modeling more generally, are well suited to modeling how patterns of symptom change during psychotherapy are related to important (e.g., therapy) outcomes. Our illustrative application of location-scale modeling showed that symptom variability was associated with less overall improvement in depressive symptoms. However, this finding requires replication with more intensive sampling of symptoms before final conclusions can be drawn on when and how to distinguish maladaptive from adaptive variability during psychotherapy. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

中文翻译：

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位置尺度建模作为心理治疗期间症状动态的综合方法：抑郁症状的插图。


目的 抑郁症状动力学，包括变化轨迹和症状变异性，与治疗结果有关。然而，这种动态通常被单独检查，并使用两步分析与感兴趣的结局相关，其特点是有几个局限性。在这里，我们将展示如何在动态结构方程建模框架中使用位置尺度模型来克服这些限制。方法 我们以可访问的方式引入位置尺度建模，为其在整合人内动力学和精神病理学干预相关变化的研究中的应用铺平道路，并在基于互联网的大规模抑郁症干预中说明了这种建模方法 （N = 1,656）。使用大约 8 周内采样的 8 个数据点，我们预测了整个干预的改善（症状减轻 50%）作为早期变化和症状变异性的函数。结果 早期症状变化与整个治疗过程中更可能的改善相关。干预期间超出变化轨迹的症状变异性与不太可能的改善相关。结论位置尺度模型和更普遍的动态结构方程模型非常适合模拟心理治疗期间症状变化模式与重要（例如治疗）结果的关系。我们对位置尺度建模的说明性应用表明，症状变异性与抑郁症状的总体改善较少相关。然而，这一发现需要通过更深入的症状采样进行复制，然后才能得出关于心理治疗期间何时以及如何区分适应不良和适应性变异性的最终结论。（PsycInfo 数据库记录 （c） 2024 APA，保留所有权利）。