I have been asked recently to write a little something about so-called "rebound headaches". This topic can be quite confusing, and as you will read, is not very well understood. The precise medical term for this disorder is Medication Overuse Headache (MOH) or analgesic rebound headache. The prevalence of this problem is about 1% in the general population and as with many types of headaches, is higher in women than in men. The underlying mechanisms for MOH are unknown, but as with many medical problems, are oftentimes multifactorial. It is known that there can be a genetic predisposition to MOH. In addition, long-term exposure to opiates is known to cause changes in the nervous system through increased expression of specific cytokines (chemicals, e.g. Calcitonin Gene-Related Peptide) and increased activity of certain neural pathways felt to modulate the sensation of pain. Some people also feel that addictive personality disorders are associated with MOH. Interestingly, migraines are the thought to be the most common "primary headache disorder" that has been linked to MOH.
