Exploring the Impact and Mechanisms of Coffee and Its Active Ingredients on Depression, Anxiety, and Sleep Disorders

Depression, anxiety, and accompanying sleep disorders are common mood disorders worldwide, significantly affecting individuals' physical and mental well-being as well as their quality of life. Coffee is a widely consumed beverage rich in bioactive compounds, including caffeine, polyphenols, tannins, proteins, and minerals, and studies suggest that coffee and its bioactive constituents demonstrate potential benefits for mental health. However, the specific mechanism by which coffee regulates depression, anxiety and sleep disorders is still unclear, and there is a lack of systematic research in this regard. This study searched four databases (PubMed, Embase, Web of Science, and Google Scholar) to summarize the effects of coffee and its active ingredients on depression, anxiety, and sleep disorders and their mechanisms. Keywords included "coffee", "active ingredients", "depression", "anxiety", "Sleep disorders "and "mechanisms". This review summarizes 27 animal studies, 11 clinical studies, and 6 epidemiological studies on this topic. The results showed that moderate caffeine intake may improve mood and cognitive performance, while excessive intake may be associated with anxiety, insomnia, and post-traumatic stress disorder (PTSD). Other compounds, such as polyphenols, may contribute to mental health through antioxidant, anti-inflammatory, and neuroprotective mechanisms. Future research is needed to clarify effective dosages, assess long-term safety, improve coffee processing methods, and explore the development of coffee-based functional foods.