Research on seasonal affective disorder (SAD) has produced several etiological models of SAD symptomatology, including a common cause model that conceptualizes symptoms as the result of a single underlying disease process and the Dual Vulnerability Model (Young et al., Journal of Affective Disorders, 22, 191–197 1991) which posits that cognitive/affective symptoms of depression are responses to vegetative symptoms (fatigue, hypersomnia, increased appetite) in individuals with a cognitive vulnerability to these seasonal changes. This study used exploratory factor analysis and network analyses to examine 22 symptoms of winter SAD in 177 adults at the start of a randomized SAD treatment trial (Rohan et al., American Journal of Psychiatry, 172, 862–9 2015). The factor analysis supported a novel four-factor model that included Negative Cognition, Loss of Vitality, Increased Appetite/Weight and Dysregulation across symptom domains. The results of the network model of interacting symptoms paralleled those of the factor analysis in producing four clusters of inter-correlated symptoms. A directed acyclic graph was constructed to model possible causal relations between symptom factors/clusters. Results suggest that vegetative symptoms (Loss of Vitality and Appetite/Weight) contribute to Dysregulation and that Loss of Vitality and Dysregulation contribute to Negative Cognition, supporting the overall structure of the Dual Vulnerability Model but with greater symptom differentiation. Findings have implications for how SAD should be researched (e.g., clusters vs. diagnosis or individual symptoms), opportunities for intervention, and the expected course of onset and remission.

对季节性情感障碍（SAD）的研究已经产生了几种SAD症状的病因模型，包括将单一潜在疾病过程的结果概念化的常见病因模型和双重脆弱性模型（Young等，《情感障碍杂志》， 22，191-197 1991），其假定，抑郁症的认知/情感症状是对植物性症状（疲劳，嗜睡，食欲增加）的个体与认知易受这些季节的变化的响应。这项研究使用探索性因素分析和网络分析在随机SAD治疗试验开始时检查了177名成年人中22种冬季SAD症状（Rohan等，《美国精神病学杂志》，172，2015年862–9日）。因子分析支持一种新颖的四因子模型，该模型包括否定认知，活力丧失，食欲/体重增加和症状域调节异常。相互作用症状的网络模型的结果与因子分析的结果平行，从而产生了四组相互关联的症状。构建了有向无环图，以对症状因素/群体之间的可能因果关系建模。结果表明，植物性症状（生命力和食欲/体重的下降）会导致机体失调，而生命力和机能失调会导致负面认知，这支持双重脆弱性模型的整体结构，但症状分化更大。研究结果对应如何研究SAD产生了影响（例如，聚类vs.