Non-response in chronic migraine: separating residual afferent drive from drive-independent persistence.

Many patients with chronic migraines struggle to find effective treatments. About 33% do not respond to any preventive drugs available. This includes medications like CGRP antibodies and onabotulinumtoxinA. Researchers looked at various studies from 2015 to 2026. They found two main reasons for treatment failure that are not biological. First, measuring headache reduction can be misleading at high headache frequencies. Second, overusing acute migraine medications can lead to treatment failure. The study suggests two underlying mechanisms for ongoing pain. One mechanism involves persistent afferent drive through pathways that treatments do not block. The other involves a central pain state that remains even after the initial triggers are reduced. Researchers also found that measuring allodynia between migraine attacks can help distinguish between patients who respond to treatment and those who do not. This insight could improve patient care and treatment strategies. Clinical relevance: This study highlights the need for tailored migraine treatments based on individual patient responses and underlying mechanisms.