The relationship between skin diseases and mental illnesses has been extensively studied using cross-sectional epidemiological data. Typically, such data can only measure association (rather than causation) and include only a subset of the diseases we may be interested in. In this paper, we complement the evidence from such analyses by learning an overarching causal network model over twelve health conditions from the Google Search Trends Symptoms public data set. We learned the causal network model using a dynamic Bayesian network, which can represent both cyclic and acyclic causal relationships, is easy to interpret and accounts for the spatio-temporal trends in the data in a probabilistically rigorous way. The causal network confirms a large number of cyclic relationships between the selected health conditions and the interplay between skin and mental diseases. For acne, we observe a cyclic relationship with anxiety and attention deficit hyperactivity disorder (ADHD) and an indirect relationship with depression through sleep disorders. For dermatitis, we observe directed links to anxiety, depression and sleep disorders and a cyclic relationship with ADHD. We also observe a link between dermatitis and ADHD and a cyclic relationship between acne and ADHD. Furthermore, the network includes several direct connections between sleep disorders and other health conditions, highlighting the impact of the former on the overall health and well-being of the patient. Mapping disease interplay, indirect relationships, and the key role of mediators, such as sleep disorders, will allow healthcare professionals to address disease management holistically and more effectively. Even if we consider all skin and mental diseases jointly, each disease subnetwork is unique, allowing for more targeted interventions.

翻译：皮肤疾病与精神疾病之间的关系已通过横断面流行病学数据得到广泛研究。这类数据通常仅能衡量关联性（而非因果性），且仅涵盖我们可能感兴趣的部分疾病。本文通过从谷歌搜索趋势症状公共数据集中学习十二种健康状况的全局因果网络模型，补充了此类分析中的证据。我们采用动态贝叶斯网络学习因果网络模型，该模型既能表示循环与非循环因果关系，易于解释，并能以概率论严格方式解释数据中的时空趋势。该因果网络证实了所选健康状况之间存在大量循环关系，以及皮肤疾病与精神疾病之间的相互作用。对于痤疮，我们观察到其与焦虑症和注意力缺陷多动障碍（ADHD）存在循环关系，并通过睡眠障碍与抑郁症存在间接关系。对于皮炎，我们发现其与焦虑症、抑郁症和睡眠障碍存在有向关联，并与ADHD形成循环关系。我们还观察到皮炎与ADHD之间的关联，以及痤疮与ADHD之间的循环关系。此外，该网络包含睡眠障碍与其他多种健康状况之间的直接连接，突显了前者对患者整体健康与福祉的影响。绘制疾病相互作用、间接关系及中介因素（如睡眠障碍）的关键作用，将有助于医疗专业人员更全面、更有效地进行疾病管理。即使我们同时考虑所有皮肤与精神疾病，每种疾病子网络仍具有独特性，从而支持更具针对性的干预措施。