Low-grade irregular fever, insomnia, anorexia, and irritability affected a psychoneurotic woman for months. She habitually drank an excessive amount of coffee. Fever and the symptoms disappeared after the intake of coffee was reduced. Fever is one of the manifestations of caffeinism.
Reimann HA. CaffeinismA Cause of Long-Continued, Low-Grade Fever. JAMA. 1967;202(12):1105–1106. doi:10.1001/jama.1967.03130250087023