Migraines Explained: Types, Triggers and Treatment Options

How Common Is Migraine, and How Is It Defined?

The World Health Organization describes migraine as a primary headache disorder that is usually episodic, lasting between 4 and 72 hours, with symptoms that can include nausea, vomiting, and sensitivity to light and sound, sometimes preceded by a visual or sensory aura. The WHO fact sheet on headache disorders states that headache disorders overall affected an estimated 3.1 billion people, or about 40% of the global population, in 2021, and that migraine ranked as the third-highest cause of disability-adjusted life years (DALYs) worldwide.

A study published in 2024 covering the period 1990 to 2021 and reviewed via PubMed Central put the global number of migraine cases specifically at 1.16 billion in 2021, equivalent to roughly 14% of the world's population, up 58.15% from 732.56 million cases in 1990. The same analysis found women carried a substantially higher absolute burden than men in 2021 (725.24 million female cases versus 433.19 million male cases), while age-standardized prevalence grew faster among men between 1990 and 2021. The study also described migraine as the second-leading contributor to the global burden of neurological diseases.

The Four Recognized Phases of a Migraine Attack

According to the American Migraine Foundation (AMF), a migraine attack can unfold in up to four phases, though not everyone experiences all of them before every attack.

Migraine With Aura, Without Aura, and Chronic Migraine

The aura phase involves temporary, reversible sensory disturbances, most often visual, but it does not occur in every attack or every person with migraine. The International Classification of Headache Disorders (ICHD-3) criteria, as summarized in a study published in PubMed Central, define chronic migraine as headache occurring on 15 or more days per month for at least 3 months, with at least 8 of those days showing specific migraine features, migraine-with-aura features, or headaches that respond to a triptan or ergot medication. Attacks that occur less frequently than this threshold are generally classified as episodic migraine.

Common Triggers

The Migraine Trust, a UK-based charity focused on headache disorders, lists a range of factors reported by people with migraine as potential attack triggers, while noting that evidence for some of them — particularly specific foods — is limited, and that combinations of factors, rather than a single trigger, often precede an attack.

• Hormonal changes, particularly falling estrogen levels around menstruation or menopause
• Stress, including the drop in stress hormones during relaxation (so-called 'let-down' migraine)
• Both insufficient sleep and oversleeping, or changes to a normal sleep pattern
• Skipping meals, which can lower blood sugar
• Caffeine, in both excess and sudden withdrawal
• Alcohol, with red wine reported most often
• Dehydration and intensive exercise
• Bright or flickering lights, strong odors, loud noise, weather changes and prolonged screen time

The Migraine Trust recommends keeping a migraine diary to spot patterns and favors broad lifestyle steps — a regular sleep and meal routine, balanced diet, regular exercise and stress management — over trying to eliminate every possible trigger, since some factors such as weather cannot be controlled.

Acute and Preventive Treatment Approaches

The WHO fact sheet groups migraine treatment into medication used during an attack (analgesics, anti-emetics and migraine-specific drugs) and prophylactic, or preventive, drugs taken regularly to reduce how often attacks occur. It also lists non-pharmacological measures: limiting alcohol, keeping a regular sleep and exercise routine, following a healthy diet, staying hydrated, and tracking headaches.

Among migraine-specific drug classes, the calcitonin gene-related peptide (CGRP) pathway has been a focus of newer treatments. According to the Association of Migraine Disorders, CGRP is a protein released by nerve endings during an attack that contributes to pain, inflammation and blood vessel dilation. Two drug categories target this pathway: CGRP monoclonal antibodies — erenumab (Aimovig), fremanezumab (Ajovy), galcanezumab (Emgality) and eptinezumab (Vyepti) — which are used only for prevention, and gepants, small molecules that block the CGRP receptor. Among gepants, rimegepant (Nurtec) is approved for both acute and preventive use, ubrogepant (Ubrelvy) and zavegepant (Zavzpret) for acute treatment, and atogepant (Qulipta) for prevention, the organization states.

Barriers to Care

The WHO fact sheet notes that headache disorders, including migraine, remain underdiagnosed and undertreated worldwide, pointing to limited awareness of their impact among health workers and policymakers, and the fact that most people with headache disorders self-manage rather than seek medical care.