Effect of green tea on reward learning in healthy individuals: a randomized, double-blind, placebo-controlled pilot study

Abstract

BackgroundBoth clinical and preclinical studies revealed that regular intake of green tea reduced the prevalence of depressive symptoms, as well as produced antidepressant-like effects in rodents. Evidence proposed that disturbed reward learning has been associated with the development of anhedonia, a core symptom of depression. However, the relationship between green tea and reward learning is poorly investigated. Our goal was to test whether chronic treatment with green tea in healthy subjects affects the process of reward learning and subsequently regulates the depressive symptoms.MethodsSeventy-four healthy subjects participated in a double-blind, randomized placebo-controlled study with oral administration of green tea or placebo for 5weeks. We used the monetary incentive delay task to evaluate the reward learning by measurement of the response to reward trial or no-reward trial. We compared the reaction time of reward responsiveness between green tea and placebo treatment. Furthermore, we selected Montgomery-Asberg depression rating scale (MADRS) and 17-item Hamilton Rating Scale for Depression (HRSD-17) to estimate the depressive symptoms in these two groups.ResultsThe results showed chronic treatment of green tea increased reward learning compared with placebo by decreasing the reaction time in monetary incentive delay task. Moreover, participants treated with green tea showed reduced scores measured in MADRS and HRSD-17 compared with participants treated with placebo.ConclusionsOur findings reveal that chronic green tea increased the reward learning and prevented the depressive symptoms. These results also raised the possibility that supplementary administration of green tea might reverse the development of depression through normalization of the reward function.

Herbal medicine for depression and anxiety:Asystematic review with assessment of potential psycho‐oncologic relevance

“…Extracts from gotu kola ( Centella asiatica ; Bradwejn, Zhou, Koszycki, & Shlik, ), green tea ( Camelia sinensis ; Zhang et al, ), holy basil ( Ocimum sanctum ; Sampath, Mahapatra, Padhi, Sharma, & Talwar, ), and Sceletium tortuosum (Terburg et al, ) when administered to healthy adults were more effective than placebo in reducing anxiety and/or depression scores.…”

Mechanisms Underlying the Anti-Depressive Effects of Regular Tea Consumption

“…The results show chronic treatment of green tea increased reward learning compared with placebo by decreasing the reaction time in monetary incentive delay task. Moreover, participants treated with green tea showed reduced scores measured in MADRS and HRSD-17 compared with participants treated with placebo [27].…”

Adaptive Cellular Stress Pathways as Therapeutic Targets of Dietary Phytochemicals: Focus on the Nervous System

“…Interestingly, a large longitudinal study showed that caffeinated coffee consumption is associated with a reduced risk of depression (Lucas et al, 2011). It was also reported that ingestion of green tea has a preventative effect on the development of depression in mice and humans Zhang et al, 2013). Therefore, there is considerable evidence that some dietary phytochemicals protect the brain against stress.…”