Background Research investigating predictors of side-effect expectations is disparate and largely based on hypothetical vignettes. Purpose To carry out a secondary analysis of a randomized controlled trial and investigate the predictors of side-effect expectations for side-effects that were, or were not, warned about. Methods Two hundred and three healthy adults completed measures concerning demographics, psychological factors, baseline symptoms, and medication-related beliefs before reading one of two types of patient information leaflet (PIL) (standard or positively framed PIL) for a sham medication and asking them about their side-effect expectations. Associations between these measures and side-effect expectations whilst controlling for the PIL received were assessed using regression analyses. Results 82.8% of participants expected side-effects that were warned about in the PIL, and 29.1% expected side-effects that were not warned about. Participants who were younger, from White backgrounds, less optimistic, experienced increased anxiety and received the standard PIL were more likely to expect side-effects that were warned about. Those with higher beliefs about medicine overuse and lower trust in medicine development were more likely to expect side-effects that were not warned about. Higher somatization, baseline symptoms, modern health worries scores, and lower trust in pharmaceutical companies were associated with increased expectations for all side-effects. The results suggest we can not only rely on altering side-effect risk communication to reduce side-effect expectations and therefore nocebo effects. We must also consider patients’ beliefs about trust in medicines. More work is needed to investigate this in a patientsample in which the medication is known to them.

中文翻译：

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预测患者信息传单中警告与未警告的副作用的预期

背景研究调查副作用预期的预测因素是不同的，并且主要基于假设的小插曲。目的 对一项随机对照试验进行二次分析，并调查对已警告或未警告的副作用的副作用预期预测因子。方法 203 名健康成年人完成了有关人口统计、心理因素、基线症状和药物相关信念的测量，然后阅读两种类型的患者信息传单 (PIL)（标准或正框 PIL）中的一种以获取假药物并询问他们关于他们的副作用预期。使用回归分析评估这些措施与副作用预期之间的关联，同时控制收到的 PIL。结果 82。8% 的参与者预计会出现 PIL 中警告过的副作用，而 29.1% 的参与者预计会出现未警告过的副作用。来自白人背景、较不乐观、焦虑增加并接受标准 PIL 的参与者更有可能期待被警告过的副作用。那些对药物过度使用有更高信念和对药物开发信任度较低的人更有可能期待没有警告过的副作用。较高的躯体化、基线症状、现代健康担忧评分以及对制药公司的较低信任与对所有副作用的预期增加有关。结果表明，我们不仅可以依靠改变副作用风险沟通来减少副作用预期，从而减少反安慰剂效应。我们还必须考虑患者对药物信任的信念。需要更多的工作来在他们知道药物的患者样本中对此进行调查。