2016 年 75 巻 2 号 p. 33-40
It is well known that stress induces or aggravates vertigo/dizziness and that dizzy patients have often comorbid psychiatric diseases such as anxiety and depression. Dizziness-associated psychiatric disease is not idiopathic but is usually an adjustment disorder to stressful life events. Stress can be divided into two groups: physical and psychological stress. Psychological stress activates the amygdala, which is a center for emotion discriminating discomfort from comfort, followed by hypothalamic-pituitary-adrenal axis (HPA axis) activation. In dizzy patients, sensory mismatch signals arising from multimodal sensory systems, including the vestibular, visual, and proprioceptive systems, would also activate the amygdala. Together with psychological stress, sensory mismatch signals judged as discomfort signals by the amygdala may drive the HPA axis and bring about dizziness. This scheme can well explain why psychological stress induces or aggravates vertigo and dizziness. In treating dizzy patients with stress-induced anxiety and depression, it is important to take care of comorbid psychiatric diseases and the cause of stress regardless of the existence or absence of organic vestibular diseases.