Abstract
Spasmodic dysphonia (SD) is known to be, not a psychiatric disease, but a type of local dystonia. However, we have experienced many patients with SD and have noticed that it is not rare for such patients to have negative emotions. We herein investigated the distinctive features of SD compared those of with other psychiatric diseases of otolaryngology using interviews, psychiatric tests and questionnaires. Most SD patients are under 30 years of age and have been affected for more than two years. These features are clearly different from those of abnormal sensations in the throat or glossodynia. The proportion of SD patients who exhibit a tendency toward neurosis as a CMI is remarkably lower (12.9%) than that observed in patients with the above-mentioned psychiatric diseases. On the other hand, SD patients more often exhibit a tendency toward an irritable personality as a CMI. Such patients are often in situations that require them to speak a lot and are worried about voice strangulation of unclear etiology. These patients are not worried due to anxiety or fear, as in social anxiety disorder (SAD), but rather demonstrate a kind of irritability. A distinctive feature of SD is that the patient feels distressed to make phone calls, especially in noisy environments. This is because they try to speak loudly and may also experience some distortion in communication. We conclude the following：SD can occur due to character, environment, expected anxiety, a defensive posture and a long affected period and be strengthened by a second circuit of increased subglottic pressure and tight vocal cord closure. It is not easy to cut this circuit；therefore, we suggest that the best treatment method is Isshiki's thyroplasty type Ⅱ.
