Green tea might be effective in alleviating COVID-19 associated psychiatric complications: preliminary results from a pilot randomized controlled trial
Authors: Mahdavi-Roshan Marjan , Salari Arsalan , Mohammadyari Eshagh , Yaghubi Kalurazi Tofigh , Pourkazemi Aydin , Vakilpour Azin , Rahbar Taramsari Morteza , Ghorbani Zeinab 
Published: October 2021

Purpose
It is argued that COVID-19 patients show various neuropsychiatric symptoms, including fatigue, depression and anxiety. On the other hand, epidemiological and experimental evidence indicated that green tea could potentially have antiviral effects and ameliorate psychiatric disorders. However, there is a lack of clinical evidence. The purpose of this study was to investigate whether drinking green tea can clinically improve psychiatric complications of COVID-19 infection.

Design/methodology/approach
This study included 40 patients with laboratory confirmed mild-to-moderate COVID-19 disorder in the current randomized open-label controlled trial. Patients were instructed to include three cups/day of green tea (intervention) or black tea (control) to their usual diet for four weeks immediately after diagnosis of the disease. At the study baseline and after the intervention, the enrolled patients’ fatigue, depression and anxiety were assessed by the Chalder Fatigue Scale, Beck Depression Inventory-Fast Screen and State-Trait Anxiety Inventory questionnaires.

Findings
A total of 19 COVID-19 cases in the intervention group (mean age = 52 years) and 14 cases (mean age = 50 years) in the control group completed the study. Analysis of covariance adjusted for baseline levels, and confounders revealed that those who consumed three cups/day of green tea compared to the patients who received black tea experienced significantly lower fatigue, depression and state and trait anxiety levels (adjusted means for fatigue = 12.3 vs 16.2 (P = 0.03), depression = 0.53 vs 1.8 (P = 0.01), 37.4 vs 45.5 (P < 0.01) and 37.9 vs 45.2 (P < 0.01)).

Research limitations/implications
The open-label design may bias the evaluation of the self-reported status of fatigue, depression or anxiety as the main outcomes assessed. Moreover, as this study did not include patients with severe COVID-19, this might affect the generalizability of the present results. Thus, the recommendation of daily drinking green tea may be limited to the subjects diagnosed with mild-to-moderate type of infection or those with long-term neuropsychiatric complications owing to COVID-19. Besides, considering the ethical issues, this study could not exclude the drug therapy’s confounding effects; thereby, this point should be considered when interpreting the current results. Besides, it is worth noting that Guilan province in the north of Iran is recognized as a tea (and particularly green tea) producing region; thereby, it is an available and relatively inexpensive product. Considering this issue, the recommendation to consume this medicinal plant in adjunct to the routine treatment approach among patients with mild-to-moderate COVID-19 based on its beneficial effects may be widely accepted.

Practical implications
Green tea consumption could be considered an option to combat COVID-19 associated psychological complications, including fatigue, depression and anxiety among patients suffering from mild-to-moderate type of this viral infection.

Originality/value
To the best of the authors’ knowledge, in this study, for the first time, the effects of green tea compared to black tea on COVID-19 associated fatigue, depression and anxiety status within an open-label controlled trial have been investigated.