Chang Shyr-Shea, Chou Tom
Department of Mathematics, University of California, Los Angeles, Los Angeles, California, USA.
Comput Psychiatr. 2018 Dec;2:205-222. doi: 10.1162/cpsy_a_00021.
Bipolar disorder is a common psychiatric dysfunction characterized by recurring episodes of mania and depression. Despite its prevalence, the causes and mechanisms of bipolar disorder remain largely unknown. Recently, theories focusing on the interaction between emotion and behavior, including those based on dysregulation of the so-called behavioral approach system (BAS), have gained popularity. Mathematical models built on this principle predict bistability in mood and do not invoke intrinsic biological rhythms that may arise from interactions between mood and expectation. Here we develop and analyze a model with clinically meaningful and modifiable parameters that incorporates the interaction between mood and expectation. Our nonlinear model exhibits a transition to limit cycle behavior when a mood-sensitivity parameter exceeds a threshold value, signaling a transition to a bipolar state. The model also predicts that asymmetry in response to positive and negative events can induce unipolar depression/mania, consistent with clinical observations. We analyze the model with asymmetric mood sensitivities and show that large unidirectional mood sensitivity can lead to bipolar disorder. Finally, we show how observed effects of lithium- and antidepressant-induced mania can be explained within the framework of our proposed model.
双相情感障碍是一种常见的精神功能障碍，其特征为躁狂和抑郁反复发作。尽管其发病率很高，但双相情感障碍的病因和机制在很大程度上仍不为人知。最近，关注情绪与行为之间相互作用的理论，包括那些基于所谓行为趋近系统（BAS）失调的理论，越来越受到关注。基于这一原理构建的数学模型预测情绪具有双稳态，且不涉及可能由情绪与期望相互作用产生的内在生物节律。在此，我们开发并分析了一个具有临床意义且可修改参数的模型，该模型纳入了情绪与期望之间的相互作用。当情绪敏感性参数超过阈值时，我们的非线性模型会表现出向极限环行为的转变，这表明向双相状态的转变。该模型还预测，对正负事件反应的不对称会诱发单相抑郁/躁狂，这与临床观察结果一致。我们分析了具有不对称情绪敏感性的模型，并表明单向情绪敏感性过高会导致双相情感障碍。最后，我们展示了如何在我们提出的模型框架内解释锂盐和抗抑郁药诱发躁狂的观察效应。
