The thing that differentiates chronic migraine from episodic migraine is how many days the migraine sufferer experiences migraines per month. Episodic migraines are defined as those which take place on fourteen days or fewer per month, while chronic migraines are fifteen or more headache days per month.
Chronic migraines have been shown to bring a greater individual and societal burden as those who experience them are “significantly more disabled than those with EM (episodic migraines) and have greater impaired quality of life both inside and outside the home”.
While not everyone who has chronic migraines will have them after having experienced episodic migraines first, some do have chronic migraines which are a result of worsened episodic migraines. Annually around 2.5% of those who experience episodic migraines see their migraines progress into being chronic migraines. This worsening is something which both sufferers and researchers are keen to find out more about in an effort to prevent as many migraine sufferers as possible from seeing their episodic migraines grow into chronic migraines.
Recent data from a systemic review of previous research (which ruled out biases and poor-quality studies) pointed to a few main factors which contribute to the progression of episodic migraines into chronic migraines. These are depression, medication overuse, allodynia (where harmless stimuli cause pain), and receiving a low income.
Those who suffered from depression were 58% more likely to have their episodic migraines become chronic, while medication overuse increased the odds of developing chronic migraines by 8.8 times. Allodynia increased the chances of episodic migraines turning chronic by 40%, and receiving an annual income below the $50,000 mark increased the likelihood of going from episodic to chronic by 35%. It was suggested that a reason for the low income risk may be that a higher income allowed sufferers access to information and treatments which prevented migraines becoming chronic.
Being aware of what the risk factors are when it comes to developing chronic migraines can help both migraine sufferers and medical professionals alike to guard against this unwanted migraine evolution, and to be vigilant in watching for any signs of episodic migraines becoming chronic migraines. Prevention is so important, as too is fast action if the problem arises.