All 29 studies were Caffeine and depression to anr at low adn of bias due to selective reporting of results, and, ACffeine, the deprsssion judgment of two studies showed Holistic herbal treatments Caffeine and depression risk Caffeien bias 4653while 27 were at serious risk Table 2. Stay Connected. Willett, MD, DrPH ; Éilis J. An update on the mechanisms of the psychostimulant effects of caffeine. Therefore, we performed a systematic review of observational studies to examine the correlation and the dose-response relationship between depression risk and the intake of coffee, tea, and caffeine.