Researchers in China conducted a meta-analysis of randomised controlled trials (RCTs) and observational studies. They found that caffeine intake is associated with an elevated risk of anxiety in healthy individuals without psychiatric disorders, especially when the intake dose is greater than 400 mg. They also pointed out that caffeine can produce anxiety or exacerbate anxiety in adults with pre-existing anxiety disorders
“This meta-analysis included 546 participants for caffeine intake and identified that caffeine intake was significantly associated with increased risk of anxiety in healthy people,” wrote the researchers in Frontiers in Psychology.
“Overall, this is also consistent with a number of findings from other literature and, combined with quantitative analyses, suggests an anxietogenic effect of caffeine in healthy populations,” said the researchers.
The researchers said that coffee consumption can have a powerful impact on long-term health due to the presence of bioactive substances such as caffeine and alkaloids, which have potential antioxidant, anti-inflammatory or anti-cancer effects. Caffeine is a key component in coffee, and is classified as a central nervous system stimulant, which means it has an impact on brain activity.
Several epidemiologic studies have found a link between caffeine and anxiety, but the results of the existing literature are inconsistent. Since the results from studies on relationship between caffeine intake and risk of anxiety remains controversial, the researchers conducted a meta-analysis to summarise the evidence about the association between caffeine intake and the risk of anxiety.
Data was obtained from eight articles, from which 546 participants were included in the caffeine-anxiety analyses. Two studies were conducted in Europe, two in Tunisia, three in America and one in Korea.
The study participants were healthy individuals without psychiatric disorders.
When analysing anxiety levels, the researchers looked at the average (mean) anxiety score for the entire cohort and compared the deviation of each individual score from that mean.
The researchers suspected that the amount of caffeine consumed might affect anxiety levels. After reviewing the effects of different doses of caffeine, they found that those who consumed the high-dose caffeine of more than 400 mg had a significantly higher increased risk of anxiety than those who took the low-dose caffeine below 400 mg.
“The results confirm that caffeine intake is associated with an elevated risk of anxiety in healthy individuals without psychiatric disorders, especially when the intake dose is greater than 400 mg,” said the researchers.
In terms of overall effect, the results of the meta-analysis showed that caffeine intake increased the risk of anxiety.
The researchers raised some important points for consideration.
Firstly, caffeine can interact with clinical treatments. Therefore, clinicians should consider the potential effects of caffeine in the treatment of psychiatric disorders, and that caffeine consumption be appropriately assessed for a more individualised treatment strategy.
Secondly, caffeine can produce anxiety or exacerbate anxiety in adults with pre-existing anxiety disorders. However, the doses associated with these effects are large (1–2 g of caffeine/day) and most people do not consume this amount of caffeine. Researchers have suggested that those who experience anxiety effects from caffeine may avoid it, and that would reduce any likelihood of caffeine-induced anxiety.
Lastly, the researchers do not recommend a caffeine intake of more than 400 mg per day.
“In summary, the results of our meta-analysis suggest that caffeine consumption may have a detrimental effect on anxiety and may increase the risk of anxiety. This association was more pronounced at caffeine intake doses above 400 mg. Future studies should further elucidate the mechanisms of action between caffeine and anxiety from genetic risk polymorphisms to risk phenotypes. In addition, studies using a wider range of doses should be conducted to elucidate the dose–response relationship between caffeine and anxiety,” concluded the researchers.
Source: Frontiers in Psychology
DOI: https://doi.org/10.3389/fpsyg.2024.1270246
“Caffeine intake and anxiety: a meta-analysis”
Authors: Chen Liu, Licheng Wang et al.
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