The effect of cocoa-rich products on depression, anxiety, and mood: A systematic review and meta-analysis.

In the popular imaginary, cocoa-derived products, like chocolate, represent a panacea for mood and affectivity. However, whether this is a myth or a fact has yet to be clarified. A systematic review and meta-analysis were conducted according to the PRISMA guidelines to investigate the effect of cocoa-derived food on depressive and anxiety symptoms, positive and negative affect. We searched Web of KnowledgeTM and PsycINFO up to April 3, 2020. After screening 761 records, we selected nine studies. Two trials evaluated the long-term effects of cocoa consumption (>1 week), two studies the short-term effects (3 days), while five studies were conducted in acute (single administration). Random-effects meta-analyses found an overall significant effect of cocoa-rich products on depressive (Hedge's g = -0.42, 95% CI -0.67 to -0.17) and anxiety symptoms (Hedge's g = -0.49, 95% CI -0.78 to -0.19). Moreover, both positive (Hedge's g = 0.41, 95% CI 0.06 to 0.77) and negative affect (Hedge's g = -0.47, 95% CI -0.91 to -0.03) significantly improved. In all meta-analyses, the effect size was medium, while heterogeneity was low. Our findings suggest that the consumption of cocoa-rich products may improve affect and mood in the short term. However, given the short duration of trials, our results cannot be generalized to long-term intake of cocoa-derived food. Cautious interpretation is also needed due to the low number of participants and studies included in the meta-analyses.