Early signs of multiple sclerosis may emerge up to 15 years before diagnosis, potentially paving the way for earlier detection and treatment.
Researchers analysed health records from more than 12,000 people in British Columbia and found that those later diagnosed with multiple sclerosis (MS) used healthcare services at increased rates as early as 15 years before classic symptoms appeared.
The team from the University of British Columbia identified clear patterns in doctor visits long before a neurologist confirmed the condition.
The findings challenge previous assumptions about when MS begins and suggest a much longer period of subtle, non-specific symptoms.
Dr Helen Tremlett, professor of neurology at UBC’s faculty of medicine, said: “MS can be difficult to recognise as many of the earliest signs – like fatigue, headache, pain and mental health concerns – can be quite general and easily mistaken for other conditions.
“Our findings dramatically shift the timeline for when these early warning signs are thought to begin, potentially opening the door to opportunities for earlier detection and intervention.”
The researchers tracked physician visits over a 25-year period leading up to the first symptoms of MS, based on neurologists’ detailed medical assessments.
This timeframe extends well beyond most previous studies, which have typically examined just five to ten years before a patient’s first demyelinating event – nerve damage that leads to visible symptoms such as blurred vision.
Key patterns emerged over time:
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15 years before onset: GP visits increased, particularly for fatigue, dizziness, pain and mental health concerns such as anxiety and depression.
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12 years before: Visits to psychiatrists rose.
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Eight to nine years before: Appointments with neurologists and ophthalmologists became more common, possibly linked to early eye or vision issues.
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Three to five years before: Visits to emergency departments and radiology services increased.
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One year before: Visits across multiple specialties – including neurology, emergency medicine and radiology – peaked.
Dr Marta Ruiz-Algueró, postdoctoral fellow at UBC and the study’s first author, said: “These patterns suggest that MS has a long and complex prodromal phase – where something is happening beneath the surface but hasn’t yet declared itself as MS.
“We’re only now starting to understand what these early warning signs are, with mental health-related issues appearing to be among the earliest indicators.”
The prodromal phase is the early part of a disease when vague or general symptoms appear before more recognisable signs develop.
Similar patterns have been found in other neurological disorders, such as Parkinson’s disease, where symptoms like sleep disturbance or mood changes can appear years before tremors or stiffness.
While most people experiencing symptoms such as fatigue or low mood will not go on to develop MS, researchers believe that identifying and better understanding this early phase could help shorten diagnostic delays and improve long-term outcomes.
Dr Tremlett said: “By identifying these earlier red flags, we may eventually be able to intervene sooner – whether that’s through monitoring, support or preventive strategies.
“It opens new avenues for research into early biomarkers, lifestyle factors and other potential triggers that may be at play during this previously overlooked phase of the disease.”