AIMS To evaluate the effects of the two main components of a Personalised Normative Feedback (PNF) (Normative feedback only -NFO; and Consequences feedback only - CFO) compared with the full intervention (PNF) in reducing alcohol use and consequences. DESIGN Three-arm pragmatic randomised controlled trial with dismantling design and 1-, 3-, and 6-months follow-ups. SETTING Web-based among Brazilian college students. PARTICIPANTS College students (18-30 years old) who reported alcohol use in the last three months (N=5,476). INTERVENTIONS 1) full PNF - a) drinking profile; b) normative comparisons; c) practical costs; d) alcohol consequences; e) strategies to decrease risks; 2) NFO - components a, b, and e; or 3) CFO - components c, d, and e. MEASUREMENTS The primary outcome was change in AUDIT score; secondary outcomes were the number of alcohol consequences, drinking frequency, and typical/maximum number of drinks. We used Mixed Models with Multiple Imputation and Pattern-Mixture Model to account for attrition. Subgroup analyses considered participant motivation to know more about their drinking (less motivated vs motivated). FINDINGS Dismantled components reduced rather than increased AUDIT score compared to full PNF, with significant effects for NFO at 1 month (b=-0.23 95%CI: -0.46;-0.002) and for CFO at 3-months (b=-0.33 95%CI:-0.62;-0.03). Compared with PNF, NFO reduced the number of alcohol consequences at 1 month (b=-0.16 95%CI:-0.25;-0.06) and drinking frequency at 3 months (b=-0.42 95%CI:-0.79;-0.05), but increased the number of typical drinks at 6 months (b= 0.38, 95%CI:0.04;0.72). CFO reduced drinking frequency at 3 months (b=-0.37 95%CI:-0.73;-0.01). Attrition models confirmed all results, except for the NFO effect on typical drinks and drinking frequency. Subgroup analyses indicated superiority of dismantled components among the students less motivated in knowing more about their drinking. CONCLUSIONS There was no evidence that either the normative or the consequences components of a web-based Personalised Normative Feedback (PNF) intervention to reduce alcohol use and its consequences contributed to intervention effects. There was some evidence of adverse effects of PNF, and these results were driven by 20% of participants who were less motivated in knowing more about their drinking.

中文翻译：

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基于网络的大学生酒精使用个性化规范反馈干预的成分评估：具有拆解设计的实用随机对照试验

目的 评估个性化规范反馈 (PNF) 的两个主要组成部分（仅规范反馈 -NFO；仅后果反馈 - CFO）与完全干预 (PNF) 相比在减少酒精使用和后果方面的效果。设计 三臂实用随机对照试验，采用拆解设计和 1、3 和 6 个月的随访。在巴西大学生中建立网络。参与者 在过去三个月内报告饮酒的大学生（18-30 岁）（N=5,476）。干预 1) 完整的 PNF - a) 饮酒情况；b) 规范比较；c) 实际成本；d) 酒精后果；e) 降低风险的策略；2) NFO——组分a、b和e；或 3) CFO - 组件 c、d 和 e。测量 主要结果是 AUDIT 评分的变化；次要结果是酒精后果的数量、饮酒频率和典型/最大饮酒量。我们使用具有多重插补和模式混合模型的混合模型来解释损耗。亚组分析考虑了参与者更多地了解他们饮酒的动机（动机较少与动机）。结果 与完整 PNF 相比，拆解的组件降低而不是增加 AUDIT 评分，对 1 个月时的 NFO (b=-0.23 95%CI: -0.46;-0.002) 和 3 个月时的 CFO (b=-0.33 95) 有显着影响%CI:-0.62;-0.03)。与 PNF 相比，NFO 减少了 1 个月的酒精后果数量 (b=-0.16 95%CI:-0.25;-0.06) 和 3 个月的饮酒频率 (b=-0.42 95%CI:-0.79;-0.05) ，但在 6 个月时增加了典型饮料的数量（b = 0.38，95% CI：0.04；0.72）。CFO 在 3 个月时降低了饮酒频率 (b=-0. 37 95% CI：-0.73；-0.01)。损耗模型证实了所有结果，除了 NFO 对典型饮料和饮酒频率的影响。亚组分析表明，在不太愿意了解更多饮酒情况的学生中，拆解组件的优势更大。结论 没有证据表明减少酒精使用的基于网络的个性化规范反馈 (PNF) 干预的规范或后果组件及其后果有助于干预效果。有一些证据表明 PNF 有不利影响，这些结果是由 20% 的参与者推动的，他们对自己饮酒的了解较少。亚组分析表明，在不太愿意了解更多饮酒情况的学生中，拆解组件的优势更大。结论 没有证据表明减少酒精使用的基于网络的个性化规范反馈 (PNF) 干预的规范或后果组件及其后果有助于干预效果。有一些证据表明 PNF 有不利影响，这些结果是由 20% 的参与者推动的，他们对自己饮酒的了解较少。亚组分析表明，在不太愿意了解更多饮酒情况的学生中，拆解组件的优势更大。结论 没有证据表明减少酒精使用的基于网络的个性化规范反馈 (PNF) 干预的规范或后果组件及其后果有助于干预效果。有一些证据表明 PNF 有不利影响，这些结果是由 20% 的参与者推动的，他们对自己饮酒的了解较少。