A common health-food supplement might help ease the urges of people with a compulsive hair-pulling disorder called trichotillomania, U.S. researchers report.

    They tested the effectiveness of the amino acid N-acetylcysteine in a 12-week study that included 50 people with an average age of 34. Most had started compulsive hair pulling by age 12.

    Some participants were given 1,200 milligrams of N-acetylcysteine every day for the first six weeks and 2,400 milligrams a day for the next six weeks. Others were given a placebo.

    After nine weeks, hair pulling was significantly reduced among those taking the supplement. After 12 weeks, 56 percent of the participants taking the supplement reported feeling much or very much improved, compared with 16 percent of those taking the placebo.

    The results appear in the July issue of Archives of General Psychiatry.

    "Trichotillomania is compulsive in the sense that people can't control it," principal investigator Dr. Jon Grant, an associate professor of psychiatry at the University of Minnesota, said in a news release from the journal. "People feel unable to stop the behavior, even though they know it is causing negative consequences. Some people don't even know they are doing it."

    "There are people who have tried all kinds of things that have never worked," Grant said. "The reality is that if you pull your hair and it is on a noticeable part of the body, people are really disabled by this. It's not easy to go out in public if people are noticing your bald spots. Self-esteem is a huge problem. This supplement may offer hope."

    N-acetylcysteine lowers brain levels of glutamate, a chemical that triggers excitement.

    美國研究人員報告說，一種普通的保健食品增補劑可能有助于減輕患有強迫性拔毛發(fā)癥狀即拔毛發(fā)癖的人們拔毛發(fā)的沖動。

    他們對平均年齡為34歲的50名拔毛發(fā)癖者進行了為期12周的研究，測試了一種氨基酸即N-乙酰半胱氨酸的有效性，其中大多數(shù)患者在12歲起就有了強制性拔頭發(fā)的癥狀。

    在頭6周，每天給一些參與者服用1200毫克N -乙酰半胱氨酸，在后六周每天給它們服用2400毫克N -乙酰半胱氨酸。給其他人服用的是安慰劑。

    經過9個星期，那些服用該增補劑的人拔毛發(fā)的次數(shù)明顯減少。經過12周后， 與16%的服用安慰劑的人相比，經過12周后，相比16%的服用安慰劑的人，56%服用增補劑的參與者感覺強迫性拔毛發(fā)的癥狀明顯或非常明顯改善。

    該研究結果刊登在《普通精神醫(yī)學紀要》7月刊中。

    "拔毛發(fā)癖是強迫性的，人們無法自控，"首席調查員喬恩格蘭特博士，明尼蘇達大學精神病學副教授，在該雜志的一個新聞發(fā)布會上說。"人們感覺無法停止該行為，盡管他們知道這種行為會造成消極后果。而有些人甚至不知道自己在拔毛發(fā)。"

    "人們已經嘗試了各種辦法來治療拔毛發(fā)癖，可從來沒有取得任何效果，"格蘭特說。"現(xiàn)實情況是，毛發(fā)是身體上的很顯眼的部分，可患有拔毛發(fā)癖的人真的無力控制這種行為要拔掉自己的毛發(fā)。如果人們發(fā)現(xiàn)你禿頂?shù)牡胤�，到外面參加社交活動就感覺很不自在，而且自尊受到傷害。而這一增補劑可能給人們帶來了希望。"

    N -乙酰半胱氨酸能降低大腦中谷氨酸鹽的水平，而谷氨酸鹽是一種能引起興奮的化學物質。