研究發現：撓癢也可以傳染
If ever you have felt a previously undetected itch when you notice someone else scratching, you are not alone. The phenomenon of the "contagious itch" has been studied for the first time by a team of US researchers who found that itching can be visually transmitted。
Dermatologists compared 14 healthy subjects with 11 patients who had the skin condition atopic dermatitis (AD). The healthy subjects had a histamine solution, which was designed to make them itch. Others had a harmless salt solution applied. All of the 25 test subjects were then shown five-minute video clips of people scratching。
The test subjects scratched twice as much when watching the videos of someone else scratching, compared to the video of the person doing nothing, in both the healthy subjects and those with AD. The AD sufferers scratched more frequently and intensely than the healthy subjects。
That means that itching, while at times a genuine physical sensation can also be activated by the power of the brain's suggestion alone. Simply watching someone scratching - or even reading about it - can provoke the sensation。
The findings appear in The British Journal of Dermatology。
看到別人抓耳撓腮，隨即發現自己也有了撓癢癢的衝動，這種情況不只在你一人身上發生。日前美國研究人員首次研究了“傳染性瘙癢”現象，並發現“瘙癢”感覺可以視覺傳染。
皮膚病學家將受試對象分爲兩組，一組是14個健康個體，一組則是有特應性皮炎的11位患者。健康者服用了可以致癢的組胺溶液，其他人則服用了無害的鹽水。接下來25個受試對象均觀看了5分鐘的描繪人們撓癢的視頻片段。
研究人員發現，無論是健康人還是特應性皮炎患者，與觀看了描繪人們什麼都沒做的視頻的受試對象相比，觀看了“撓癢”視頻的收拾對象撓癢次數是前者的兩倍。而特應性皮炎患者比健康人士撓癢的頻率更高、程度更嚴重。
這就意味着，瘙癢有時確實是實實在在的生理體驗，但也可以單憑大腦暗示被激活。只要看別人撓癢——或者僅僅是讀到關於撓癢的文字——這種“瘙癢”感便會油然而生。
研究結果刊登於《英國皮膚病學雜誌》。
