Chronic migraine has a great detrimental influence on a patient’s life, with a severe impact on socioeconomic functioning and quality of life. Chronic migraine affects 1–2% of the general population, and about 8% of patients with migraine; it usually develops from episodic migraine at an annual conversion rate of about 3%."

However, despite many decades of intensive research :

"The physiological mechanisms that underlie development of chronic migraine are not entirely understood."

Source : Chronic migraine: risk factors, mechanisms and treatment Nature Reviews Neurology 12, 455–464 (2016)

Or as the Wikipedia page more directly puts it : "The underlying causes of migraines are unknown."

Note : Many of the first-line 'Western medicine' drugs routinely used to treat migraine work by as-yet-unknown mechanisms, e,g, Amitriptylineplugin-autotooltip__plain plugin-autotooltip_bigAmitriptyline

Amitriptyline hydrochloride - originally sold under brand names Elavil, Endep and others, is a second-line drug used to treat Major Depressive Disorder, Migraine, Parkinson's disease and, recently, Attention-Deficit / Hyperactivity Disorder (ADHD)

It was discovered more than 70 years ago, and, despite a wide range of debilitating side effects, and the discontinuation of, Lacosamideplugin-autotooltip__plain plugin-autotooltip_bigLacosamide

Lacosamide - sold under the brand name Vimpat and others - was discovered at the University of Houston in 1996. It was licenced in Europe and the US in 2008 for the treatment of partial-onset seizures in Epilepsy.

"Its precise mechanism of action was unknown at the time of approval, and the exact amino acid targets involved remain uncertain to this day.",Triptansplugin-autotooltip__plain plugin-autotooltip_bigTriptans

Triptans, sold under the brandnames Imitrex, Zomig, Amerge, Maxalt, Relpax and others, are a range of highly effective drugs used to treat Migraine and Cluster headache.

The mechanism of action of the drugs has been debated since the 1980s.

It's currently thought that Triptans work by a (possible) combination of vaso-constriction and the blocking of 5-HT ,Valproateplugin-autotooltip__plain plugin-autotooltip_bigValproate

"Valproate (VPA) and its valproic acid, sodium valproate, and valproate semisodium forms are medications primarily used to treat epilepsy and bipolar disorder and prevent migraine headaches. They are useful for the prevention of seizures in those with absence seizures, partial seizures, and generalized seizures. They can be given intravenously or by mouth, and the tablet forms exist in both long- and short-acting formulations. &etc.

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