Can coffee prevent a headache?

Stopping daily caffeine consumption produces changes in cerebral blood flow velocity that are most likely related to caffeine withdrawal symptoms including headache, drowsiness and decreased alertness, according to a recent study.

People say caffeine withdrawal is characterised by headaches, fatigue, feeling less alert and experiencing difficulties in concentrating.

Stacey Sigmon, research professor of psychiatry at the University of Vermont and colleagues at Johns Hopkins, sought to investigate the biological mechanisms of caffeine withdrawal.

They looked at 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 brain electrical activity via electroencephalogram (EEG); blood flow velocity in the brain via ultrasound; and participants' self-reports of subjective effects via questionnaires.

The team demonstrated that stopping daily caffeine consumption produces changes in cerebral blood flow velocity and quantitative EEG that are likely related to the classic caffeine withdrawal symptoms.

More specifically, acute caffeine abstinence increased brain blood flow, an effect that may account for commonly reported withdrawal headaches.

Consistent with this, volunteers reported increases in measures of "tired", "fatigue", "sluggish" and "weary". Overall, these findings provide the most rigorous demonstration to date of physiological effects of caffeine withdrawal, said a Vermont College release.

The researchers also discovered a provocative and somewhat unexpected finding - that there were no net benefits associated with chronic caffeine administration.
The paper was published online in Psychopharmacology.