For some it starts with a toothache. For others, a blind spot or creeping numbness in fingers and toes.
Warning signs for migraine and cluster headache are as individual as the debilitating range of symptoms that fall under the banner of this little-understood illness.
"I don't know what happened in my brain but it's broken, and I just have to live with it," chronic migraine sufferer Kathryn Crosby said.
One in 10 Australians suffer migraine, putting it is on par with asthma and melanoma -- and it affects women three times more than men.
The burden of migraine on the Australian economy has not been quantified but headache specialist Paul Roland predicts it is immense.
"One of the reasons migraine has such an effect on the economy is it's very prevalent when people are in their prime -- often in their 20s and 30s," Roland said.
"It essentially means these people are temporarily debilitated at unpredictable times. They may be a chief executive and will become completely unable to work for hours or days without any warning.
"Or often it's parents, and they have to explain why they can't take their child to that sport event or why they can't go to dinner with their partner."
Crosby's migraines have rendered her unable to work.
"It's taken four years of my life," she said.
For Bruce Davis, his migraines were such that he could work, but it was not easy.
"I'd have a dull migraine-type headache and that would generally stay with me during the day at work and wouldn't go away irrespective of what I took, generally until about 3pm... and I would be left with what I called a bruised feeling," Davis said.
Despite celebrities talking about their migraines, including swimmer Ian Thorpe, radio host Kyle Sandilands and global stars like Kanye West and Serena Williams, Roland said migraine is under reported.
"Despite all the campaigns and celebrities, It is vastly under diagnosed, especially in children," Roland said.
"Generally, some GPs are loathe to diagnose it and for adults, there's a sense that there's no need to report it if the treatment isn't effective.
"I think it's the case that people with migraine went to a GP about a decade ago and were told to take an aspirin, which didn't really work, so they've never been back.
"Then in terms of children, kids are long suffering -- if they feel unwell, often they'll just go quiet.
"One of my children has migraine and had I not have been a specialist in migraine, she would not have been diagnosed."
Symptoms of migraine range from severe headache to body numbness and palsy right through to nausea and vomiting.
One of the more unusual symptoms, however, is aura or visual issues including blind spots and perceived flickering lights, zig-zagging visions and photo sensitivity.
Another symptom, Roland said, was guilt.
"They suffer a lot not from the pain but from guilt," Roland said.
"It's often young women who get migraines, and for many, the trigger isn't stress itself, it's the relief of stress.
"This means a common time to get a migraine is Saturday morning, or at the start of a holiday.
"It's a feeling of letting the team down because you can't enjoy time with you loved ones."
For Alex Nisbet, who gets chronic cluster headache, the stress of an imminent attack causes tension.
"The anxiety that it creates for a large proportion of people, brings on depression," Nisbet said.
"When the pain is at a 10, it feels like there is a vice around your head there is a massive headache, and speaking is really difficult.
"You're in the fetal position, begging for something. It doesn't kill you, but that's when you wish it would."
In Australia, meanwhile, research into migraine continues, often through volunteer donations.
On Monday, not-for-profit organisation Brain Foundation announced a new grant into migraine imaging at the University of Sydney, while the Centre for Clinical Studies is currently recruiting volunteers for two separate studies into chronic migraine including one looking at the effectiveness of a breast milk stimulant.
At the University of Sydney, PHD candidate Maria Aguila last month published findings on a type of acid that was present in high levels in migraine sufferers.
"For such a debilitating condition, very little is known about migraine so this is a big step forward and could lead to better diagnosis and treatment of the disease in the future," Aguila said.
"We still don't know what causes migraine, how it starts and ends, or why the triggers appear to differ from one person to the next, but this discovery means that we can now be much more specific with our research going forward."
For Roland, it's an issue that requires more funding for research.
"I think it shows something's wrong in society today in that pain is trivialised," Roland said.
"If you've got a great, big growth hanging off your head, people will do something about it but if you've got pain and no one can see anything, it's not taken seriously.
"My advice for anyone who gets migraine is don't take no for an answer.
"Keep trying until you find something that works."