Trichotillomania is a functionally impairing, often overlooked disorder with no Food and Drug Administration-approved medications indicated for its treatment. The ability of clinical trials to detect the beneficial effects of pharmacologic treatment in trichotillomania has been hampered by the high placebo response rate. Very little is known about baseline demographic and clinical characteristics that may be predictive of placebo response in such patients. Overall, 104 participants assigned to placebo were pooled from five double-blind trials conducted at three sites in the USA and Canada. Participants were classified as placebo responders or nonresponders on the basis of a cutoff of a 35% reduction in symptom severity on the Massachusetts General Hospital Hair Pulling Scale. Baseline group differences were characterized using t-tests and equivalent nonparametric tests as appropriate. Thirty-one percent of individuals assigned to placebo treatment showed a significant clinical response to placebo. Placebo responders (n=32) and nonresponders (n=72) did not differ significantly on any demographic or clinical variable. Predictors of placebo response for trichotillomania remain elusive and do not appear to be similar to those reported for other mental health disorders.

中文翻译：

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毛滴虫病的安慰剂反应。

毛滴虫是一种功能受损的疾病，通常被忽视，没有经过美国食品药品监督管理局批准的药物可用于治疗。高安慰剂反应率阻碍了临床试验检测药物治疗对毛滴虫病的有益作用的能力。关于基线人口统计学和临床​​特征的信息知之甚少，这些基线和临床特征可预测此类患者的安慰剂反应。总体而言，在美国和加拿大的三个地点进行的五项双盲试验中，共有104名被分配给安慰剂的参与者参与其中。根据马萨诸塞州综合医院拔毛量表中症状严重性降低35％的临界值，参与者被分为安慰剂反应者或无反应者。使用t检验和适当的等效非参数检验来表征基线组差异。接受安慰剂治疗的人中有31％对安慰剂表现出明显的临床反应。安慰剂反应者（n = 32）和无反应者（n = 72）在任何人口统计学或临床变量上均无显着差异。毛滴虫病的安慰剂反应的预测因子仍然难以捉摸，并且似乎与其他精神疾病报告的相似。