Coffee and Caffeine in Depression: Symptom-Level Modulation and Challenges in Nutripsychiatric Interpretation

Background: Evidence on the relationship between coffee, caffeine and depression remains inconsistent. Observational studies often report inverse associations, whereas experimental findings indicate potential adverse effects on anxiety and sleep. As a psychostimulant, caffeine increases alertness and perceived energy and may transiently improve mood and task engagement. Objective: This narrative review aims to reinterpret existing evidence on coffee and caffeine in depression from a symptom-level perspective, with emphasis on sleep–wake regulation, anxiety sensitivity, habitual use and withdrawal-related phenomena. Methods: Human studies published between 2000 and 2025 were synthesised narratively based on their relevance to depressive symptoms, arousal regulation, sleep and behavioural patterns of caffeine use, rather than for pooled effect estimation. Results: Caffeine may transiently alleviate fatigue and psychomotor slowing, but these effects are context-dependent and frequently counterbalanced by sleep disruption, anxiety and withdrawal-related fluctuations. Inverse associations observed in cohort studies may partly reflect reverse causality, residual confounding and relief of withdrawal symptoms rather than true antidepressant effects. Conclusions: Coffee and caffeine should not be conceptualised as antidepressant interventions. Instead, they appear to act as context-dependent modulators of symptom expression in depression, particularly affecting fatigue, alertness and sleep–wake stability. Failure to account for dose, habitual use, withdrawal and individual vulnerability may lead to overinterpretation of epidemiological findings in nutripsychiatric research.