what causes a migraine

The exact underlying cause of migraines is not fully understood, though doctors view it as a complex neurological condition involving temporary changes in nerve signals, brain chemicals, and blood vessels in the brain.¹²

Underlying Factors

• Genetics: Migraines tend to run in families. If a close family member has them, your risk increases significantly (up to 80% of people have a first-degree relative with the condition).¹²
• Hormones: Women experience migraines three times more often than men, largely due to fluctuations in estrogen during menstrual periods, pregnancy, or perimenopause.¹
• Brain Activity: An attack involves nerve pathways and brain chemicals—such as calcitonin gene-related peptide (CGRP) and serotonin—that cause inflammation and pain signals in the brainstem and trigeminal nerve.¹

Common Migraine Triggers

Single factors rarely cause an attack on their own. Instead, multiple triggers build up and push a person past their personal "migraine threshold". Common triggers include:¹²

• Stress: Emotional stress or the "let-down" phase after a stressful period is one of the most frequent triggers.¹²³
• Sleep Changes: Getting too little sleep, oversleeping, or having an irregular sleep schedule.¹²³
• Dietary Factors: Skipped meals, dehydration, caffeine withdrawal or excess, and certain foods like aged cheese, chocolate, alcohol (especially red wine), or food additives like MSG and nitrates.¹²³
• Sensory Stimuli: Bright or flickering lights, loud noises, and strong smells (like perfumes, smoke, or paint).¹²³
• Environmental & Physical Factors: Weather shifts or barometric pressure changes, intense physical exertion, or poor neck and posture strain.¹²³

You can read more about managing patterns through the The Migraine Trust or look over clinical guidance via the NHS Migraine Guide.¹²If you'd like to narrow this down, let me know:

• Are you asking for yourself or someone else?
• What specific symptoms or patterns (like auras or timing around your cycle) are you noticing?

The exact root cause of migraines is not fully understood, though they are widely recognized as a neurological condition caused by a combination of genetic and environmental factors. Research indicates they involve temporary changes in brain activity, nerve pathways, and blood vessels.¹²³⁴

Underlying Factors & Susceptibility

• Genetics and family history. Migraines strongly tend to run in biological families, with up to 80% of sufferers having a close relative with the condition. Inherited genes can make a person's nervous system more sensitive to internal and external changes.¹²
• Brain chemistry and nerve pathways. Attacks are linked to waves of abnormal electrical activity in the brain and imbalances in brain chemicals. These shifts irritate the trigeminal nerve, which releases inflammatory substances around the blood vessels in the head and causes throbbing pain.¹²
• Biological sex. Women are roughly three times more likely to experience migraines than men. This gap is largely driven by shifts in female sex hormones from puberty through menopause.¹²

Common Migraine Triggers

For people predisposed to migraines, specific factors—known as triggers—can set off an attack. According to The Migraine Trust, single triggers rarely act alone; instead, several factors often build up together until they cross your personal "migraine threshold".¹²

• Hormonal fluctuations. Drops or changes in estrogen before or during menstrual periods, pregnancy, or perimenopause are major triggers for many women.
• Stress and emotional shifts. High stress, anxiety, or even the sudden drop in stress levels at the start of a weekend or holiday can bring on an attack.
• Sleep disruptions. Getting too little sleep, sleeping too much, or dealing with irregular schedules and jet lag frequently destabilize the brain's pain pathways.
• Dietary habits and dehydration. Skipping meals, fasting, and not drinking enough water are well-documented triggers. Certain items like alcohol (especially red wine), too much caffeine, caffeine withdrawal, aged cheeses, and foods with nitrates or MSG can also play a role.
• Sensory stimulation. Bright or flickering lights, sun glare, loud noises, and strong smells like perfume, paint, or cigarette smoke can overstimulate a sensitive nervous system.
• Physical and environmental changes. Sudden intense exercise, neck or jaw tension, and shifts in weather or barometric pressure can tip the balance toward an attack.
• Medication overuse. Taking acute headache or pain medications too frequently (often more than 10 days a month) can cause rebound "medication overuse" headaches.^1234567

(Note: Early warning signs of a migraine—such as neck stiffness, fatigue, or food cravings—often happen up to 24 hours before pain begins. People sometimes mistake a pre-migraine craving, like wanting chocolate, for the trigger itself.) ¹²³

Keeping a daily headache diary is often recommended by organizations like the NHS to help spot personal patterns and overlapping triggers.

Are you trying to track down your own triggers, or looking for ways to prevent or treat migraine attacks? If you'd like to share any patterns you've noticed, I can help you narrow down potential causes or management options.

A migraine is a neurological condition caused by changes in how the brain and nervous system function. It isn't simply a bad headache. Migraines can cause intense throbbing pain, nausea, sensitivity to light and sound, and sometimes visual disturbances.

🧠 What actually causes a migraine?

The exact cause isn't fully understood, but migraines are thought to involve a combination of:

1. Genetics – Migraines often run in families, meaning you may inherit a tendency to develop them.
2. Brain chemicals – Changes in chemicals such as serotonin can affect pain pathways in the brain.
3. Nerve activity – Overactivity of certain nerve pathways, particularly involving the trigeminal nerve, can trigger migraine pain.
4. CGRP – A protein called calcitonin gene-related peptide plays an important role in migraine attacks by transmitting pain signals and influencing blood vessels.

Common migraine triggers

Sleep changes

Too little sleep, too much sleep or irregular sleeping patterns.

Stress

Emotional stress, anxiety or even the sudden relaxation after a stressful period.

Food and drink

Alcohol, skipped meals, dehydration and, in some people, certain foods.

Environmental factors

Bright lights, strong smells, loud noises and weather changes.

Hormonal changes

Fluctuations in oestrogen, particularly around periods, pregnancy or menopause.

Common symptoms of a migraine

• Throbbing or pulsing headache, often on one side.
• Nausea or vomiting.
• Sensitivity to light and sound.
• Blurred vision.
• Dizziness.
• Feeling extremely tired.
• Sometimes visual aura, such as flashing lights, zigzag lines or blind spots.

What happens inside your brain?

During a migraine attack, nerve pathways become activated and release substances such as CGRP. This causes changes in pain signalling and inflammation around pain-sensitive structures in the brain.

A question that might help me understand what you're experiencing:

Are you asking because you suffer from migraines yourself, or are you just curious about what causes them?

If you experience them, I can also explain why they happen, what makes them worse and how to reduce the frequency of attacks.

If a headache comes on suddenly and is extremely severe, or comes with new weakness, confusion, loss of vision or difficulty speaking, seek emergency medical attention.