Beyond the buzz: the fatal consequences of caffeine overconsumption

Caffeine is a naturally occurring stimulant present in dozens of plant species including Coffea arabica and Camellia sinensis, from which we obtain coffee and tea, respectively. It is one of the world's most widely consumed psychoactive substances frequently used to increase alertness, elevate mood, and ward off fatigue. In traditional preparations, caffeine is generally well-tolerated by the consumer. However, complications can arise with the addition of caffeine to products like energy drinks, medications, and supplements. Furthermore, with pure caffeine accessible online, a consumer may unknowingly or inadvertently consume caffeine in dangerous amounts. Symptoms of caffeine toxicity include classic central nervous system stimulation side effects, such as agitation, insomnia, gastrointestinal distress, tachycardia, seizures, and death in extreme cases. To evaluate concentrations of toxicological significance, caffeine cases were assessed at a large reference laboratory (NMS Labs). From 2019 to 2023, 406 blood cases underwent confirmation testing via LC-MS-MS; the mean and median caffeine concentrations were 35 and 4.8 µg/mL, respectively. While most caffeine-containing cases indicate traditional use in the general population with concentrations <25 µg/mL (62%, N = 254), 10% (N = 42) of the cases were >100 µg/mL, indicating levels which may contribute to a fatal outcome. To gain insight into the significance of caffeine in determining the cause and manner of death, cases with various manners of death are presented. Despite being one of the most common toxicological findings in medicolegal death investigations, caffeine is often overlooked. Screening results should undergo scrutiny, and confirmation testing should be considered in cases where caffeine intoxication is prominently featured in the case history or scene investigation.