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

Area of Science:

• Nutripsychiatry
• Psychopharmacology
• Neuroscience

Background:

• Inconsistent evidence links coffee/caffeine to depression, with observational studies suggesting benefits but experimental data showing potential negative impacts on anxiety and sleep.
• Caffeine, a psychostimulant, can temporarily enhance alertness and mood, but these effects are complex and debated in relation to depressive symptoms.

Purpose of the Study:

• To review and reinterpret existing research on coffee and caffeine's effects on depression.
• Focus on symptom-level analysis, including sleep-wake regulation, anxiety, habitual use, and withdrawal.

Main Methods:

• Narrative synthesis of human studies published between 2000 and 2025.
• Studies selected based on relevance to depressive symptoms, arousal, sleep, and caffeine use patterns.

Main Results:

• Caffeine's benefits (e.g., reduced fatigue) are transient and context-dependent, often offset by sleep disruption, anxiety, and withdrawal.
• Observed inverse associations in studies may be due to reverse causality, confounding, or withdrawal symptom relief, not true antidepressant effects.

Conclusions:

• Coffee and caffeine should not be considered antidepressant interventions.
• They act as context-dependent modulators of depression symptoms, particularly impacting fatigue, alertness, and sleep-wake stability.
• Overinterpretation of epidemiological findings is possible without considering dose, habitual use, withdrawal, and individual vulnerability.