Breaking the cycle: Caffeine use as a self-medication strategy for fatigue and its role in sleep disturbance and anxiety: A narrative review

Caffeine is widely used to counteract fatigue and maintain alertness in demanding daily contexts. Although this strategy may be effective in the short term, repeated fatigue-driven caffeine use may have unintended consequences for subsequent sleep and emotional regulation. This narrative review aims to synthesize current evidence on caffeine use as a self-medication strategy for fatigue and to examine its potential role in sleep disturbance, hyperarousal, and anxiety-like symptoms. Targeted literature searches were conducted in PubMed, PubMed Central, and Google Scholar. Evidence from review articles, randomized controlled trials, observational studies, meta-analyses, and relevant position statements was synthesized narratively. The reviewed literature indicates that caffeine may temporarily reduce perceived fatigue and support alertness by antagonizing central adenosine receptors. However, this pharmacological effect masks fatigue rather than resolving the underlying biological need for rest. At higher doses or when consumed later in the day, caffeine may impair sleep initiation, sleep continuity, restorative sleep architecture, and perceived sleep quality. Furthermore, in susceptible individuals, escalating caffeine intake may contribute to central nervous system hyperarousal and anxiety-like symptoms, which can further disrupt sleep and reinforce next-day fatigue. Based on these findings, this review proposes a conceptual fatigue–caffeine–sleep disturbance–anxiety cycle, in which short-term fatigue management may unintentionally sustain longer-term impaired recovery. Public health and behavioral recommendations should therefore emphasize dose, timing of intake, sleep hygiene, and individual susceptibility rather than simple caffeine avoidance.