THE EFFECTS OF CAFFEINE ON ANXIETY

A high-sensitivity electronic search and which underwent peer review according to the PRESS Guide was carried out in March 2021 in the following databases as recommended by the Cochrane Handbook: Cochrane Library, MEDLINE via PUBMED, LILACS via VHL, APA PsycNet, EMBASE, Scielo, Scopus, Web Of Science and Cinahl. The eligibility criteria was Randomized clinical trials complete and available that evaluated the direct influence of caffeine through capsules or caffeinated beverages on anxiety and/or anxiety disorders in samples of healthy individuals of any age and sex. By excluding 2726 duplicates, a detailed screening of 4273 titles and abstracts was performed. The full texts of the 91 remaining studies were evaluated, of which only 27 were chosen for the qualitative synthesis. The final references were exported to a Google Sheets file, where two review authors (AN and CS) used a form to extract the characteristics of the studies: article data (authors year of publication, country of study and duration), sociodemographic data population (sex, age group, caffeine consumption habits and comorbidities) and methodological data (study design, anxiety scale instrument used to measure anxiety, scores before and after the intervention, intervention dose, time interval between measurement, intervention and new measurement and, activity performed between the intervention and measurement). The quality assesssment was conducted independently by two review authors (AN and CS), in which disagreements were resolved through discussions between the evaluators. All articles included had their methodological quality assessed, but without using it as an exclusion criterion. To this end, the Revised Cochrane Risk-of-bias Tool for Randomized Trials (Rob2) was used, a Cochrane tool recommended for analyzing the risk of bias in randomized clinical trials, in versions for parallel design trials and also for crossovers.

本研究遵循PRESS指南（PRESS Guide）开展同行评议，于2021年3月依照《Cochrane手册》（Cochrane Handbook）推荐的数据库进行高灵敏度电子检索，检索覆盖的数据库包括：Cochrane图书馆（Cochrane Library）、通过PubMed检索的MEDLINE、通过VHL检索的LILACS、APA PsycNet、EMBASE、SciELO、Scopus、Web of Science以及CINAHL。
本次检索的纳入标准为：已完成且可获取的随机对照试验（Randomized Clinical Trials, RCTs），评估以胶囊或含咖啡因饮品形式摄入的咖啡因对任意年龄、性别的健康个体样本的焦虑状态及/或焦虑障碍的直接影响。经剔除2726条重复文献后，对4273条题名与摘要进行详细筛选，最终剩余91项研究的全文被纳入评估，其中仅27项被选用于定性综合分析。
最终检索得到的文献被导出至Google Sheets表格中，由两名综述作者（AN与CS）通过预设表单提取研究特征，具体包括：文献基本信息（作者、发表年份、研究开展国家及研究周期）、研究人群社会人口学数据（性别、年龄分组、咖啡因摄入习惯与共病情况）以及方法学数据（研究设计、用于评估焦虑的焦虑量表工具、干预前后的评分、干预剂量、测量-干预-再次测量之间的时间间隔，以及干预与测量之间开展的活动）。
方法学质量评估由两名综述作者（AN与CS）独立完成，评估过程中出现的分歧通过评估者间讨论解决。所有纳入的文献均接受了方法学质量评估，但未将评估结果作为文献排除标准。本研究采用《Cochrane随机试验偏倚风险修订工具》（Revised Cochrane Risk-of-bias Tool for Randomized Trials, RoB2）完成质量评估，该工具为Cochrane推荐用于分析随机对照试验偏倚风险的专用工具，包含平行组设计试验与交叉试验两种版本。