The first signs of multiple sclerosis appear 15 years before the more common symptoms.

The first signs of multiple sclerosis (MS) can appear up to 15 years before the appearance of the first classic neurological symptoms.

Published in the journal JAMA Network Open , the study analyzed the medical records of more than 12,000 people in British Columbia, Canada, and found that those with MS began using health care services most frequently 15 years before their first MS symptoms appeared.

According to this new research from the University of British Columbia , 15 years before the onset of symptoms, patients go to the doctor for problems such as fatigue, pain, dizziness, and mental disorders such as anxiety and depression ; 12 years before, there was already an increase in visits to psychiatrists, while eight or nine years before that, there was an increase in consultations with neurologists and ophthalmologists, possibly associated with blurred vision or eye pain.

Only one year after diagnosis, consultations with doctors in various specialties—neurology, emergency medicine, and radiology—reached their peak.

The findings challenge ideas about when the disease actually begins and offer the most comprehensive picture to date of how patients engage with a variety of healthcare providers in the years before diagnosis as they seek answers to poorly defined medical challenges.

“Multiple sclerosis can be difficult to recognize, as many of the early signs—such as fatigue, headaches, pain, and mental health problems—can be quite general and easily confused with other conditions,” explains lead author Helen Tremlett, a research fellow at the Djavad Mowafaghian Centre for Brain Health . “Our findings dramatically alter the timeline at which these early warning signs are thought to begin, potentially opening the door to opportunities for earlier detection and intervention.”

The study used linked provincial, clinical, and administrative health data to record medical visits during the 25 years prior to the onset of MS symptoms in a patient, as determined by a neurologist through detailed medical history and clinical assessments.

"These patterns suggest that MS has a long and complex prodromal phase, where something is happening beneath the surface, but it hasn't yet fully manifested as MS," says Marta Ruiz-Algueró , first author of the study. "We are just beginning to understand what these early warning signs are, and mental health problems appear to be among the first indicators."

"By identifying these early warning signs, we could intervene more quickly, whether through monitoring, support, or preventative strategies," Tremlett says. "This opens up new avenues for research into early biomarkers, lifestyle factors , and other potential triggers that could be involved during this previously overlooked phase of the disease."