May 28/Pharma Investments, Ventures & Law Weekly -- According to reports from consumers of coffee and other caffeinated products, caffeine withdrawal is often characterized by a headache, fatigue, feeling less alert, less energetic and experiencing difficulty concentrating. Researchers from the University of Vermont College of Medicine and Johns Hopkins School of Medicine sought to investigate the biological mechanisms of caffeine withdrawal in a paper published recently in the online edition of the scientific journal Psychopharmacology. They investigated brain electrical activity and blood flow during caffeine withdrawal to examine what was taking place physiologically during acute caffeine abstinence, including the likely mechanism underlying the common "caffeine withdrawal headache."
The group examined caffeine's effects in a double-blind study, which involved the administration of caffeine and placebo capsules. Each participant's response to the caffeine or placebo was measured using three different measures: brain electrical activity via electroencephalogram (EEG); blood flow velocity in the brain via ultrasound; and participants' self-reports of subjective effects via questionnaires.