Expert input: Dr Shubha Subramanian, Consultant Neurologist
When people think of dementia, they often picture an elderly person struggling to recognise loved ones or remember familiar places. Memory loss has long been considered the defining hallmark of the condition. But scientists are now painting a far more complex picture—one in which dementia may begin silently, decades before the first forgotten name or misplaced key.
Increasingly, researchers believe that the earliest signs of dementia may emerge during mid-life, not in the form of memory problems, but through subtle changes in mood, emotional wellbeing, attention and behaviour. What many dismiss as stress, burnout or the emotional toll of juggling careers, family and ageing parents could, in some cases, reflect changes occurring much earlier within the brain.
As populations age and dementia cases continue to rise worldwide, experts are calling for a shift in focus—from recognising dementia when memory fails to protecting brain health long before cognitive decline becomes obvious.
A landmark study by researchers at University College London (UCL), published in The Lancet Psychiatry, followed more than 5,000 adults aged 55 years and above for almost two decades. The findings were striking. Participants who experienced persistent depressive symptoms during mid-life had a significantly higher risk of developing dementia later in life. The study adds to growing evidence that dementia is not a disease that suddenly appears in old age. Instead, the biological changes that eventually lead to dementia may begin years—even decades—before diagnosis.
A disease that unfolds over time
According to Dr. Shubha Subramanian, Consultant Neurologist, dementia should not be viewed as a condition that appears overnight. “Dementia is actually a spectrum. It often begins with mild cognitive impairment, which is considered the pre-dementia stage, and gradually progresses to dementia. There are many subtle details that need to be recognised. Unfortunately, by the time patients reach a neurologist, they usually present with full-blown symptoms.”
This gradual progression explains why early diagnosis remains challenging. The warning signs can be vague, inconsistent and easily mistaken for the pressures of modern life.
The brain may first speak through emotions
One of the biggest misconceptions about dementia is that memory loss is always the earliest symptom. In reality, neurologists are increasingly recognising that emotional and behavioural changes may appear much earlier.
Dr. Shubha says persistent mood disturbances deserve careful attention. “People should not ignore frequent mood fluctuations, unexplained crying episodes, excessive emotional reactions, anxiety, depression or suicidal thoughts. Sometimes these may simply reflect environmental stress, but they can also indicate an underlying psychiatric condition that requires evaluation.”
Importantly, these symptoms do not automatically mean dementia is developing. However, they should never be brushed aside as “just stress,” especially when they persist or interfere with daily life.
Stress, burnout or something more?
Forgetfulness during the forties and fifties has become almost normal. Long work hours, financial pressures, caregiving responsibilities, poor sleep and constant digital distractions make many people feel mentally exhausted.
So how can someone distinguish ordinary stress from something more concerning? “The patient cannot make that distinction alone,” says Dr. Shubha. “This requires clinical expertise. If someone notices persistent symptoms, it is better to consult a neurologist or psychiatrist. They can determine whether the problem is related to stress, depression, anxiety or an early cognitive disorder.”
Self-diagnosis, she cautions, often leads to unnecessary anxiety—or worse, delayed medical attention.
When depression imitates dementia
Mental health and cognitive health are closely intertwined.
Long-standing stress, anxiety and depression not only reduce quality of life but can also affect how the brain processes information.
Dr. Shubha explains that doctors often encounter a condition known as pseudodementia.
“These patients do not actually have dementia. Because of underlying depression or psychological stress, they develop poor attention. When attention is impaired, information never gets properly stored as memory.”
In other words, many people who believe they are developing dementia are actually struggling with concentration rather than memory itself.
“When patients complain that they cannot remember things, the problem is often not memory loss but inattention. If the brain never fully registers information because attention is poor, there is nothing to remember later.”
Unlike true dementia, pseudodementia is often reversible when the underlying depression or anxiety is appropriately treated.
Protecting the brain begins long before old age
The encouraging news is that many risk factors for cognitive decline can be modified.
Dr. Shubha believes brain health should become a priority during mid-life rather than after retirement. A nutritious diet rich in fruits, vegetables, good-quality proteins and healthy fats provides the foundation for healthy brain ageing. Regular aerobic exercise—at least five days a week—combined with strength training improves blood flow to the brain while reducing the risk of vascular disease.
But protecting the brain involves far more than eating well and exercising. “The brain needs continuous stimulation. Develop hobbies outside your profession. Learn a musical instrument, learn a new language, read regularly or acquire a new skill. Keeping the brain active throughout life helps maintain cognitive function,” she emphasises.
These activities strengthen neural connections and contribute to what neurologists call cognitive reserve—the brain’s ability to compensate for age-related changes.
The role of lifestyle diseases
Brain health cannot be separated from overall physical health. Conditions such as diabetes, hypertension, obesity and cardiovascular disease significantly increase the risk of stroke and vascular dementia. Dr. Shubha stresses the importance of keeping these conditions under control through regular medical care while also avoiding smoking, limiting alcohol intake, maintaining healthy sleep patterns and reducing sedentary behaviour. Poor sleep, she adds, is increasingly recognised as another important contributor to long-term cognitive decline.
Changing the conversation around dementia
For decades, dementia awareness has centred on memory loss. But science is steadily shifting that narrative. The earliest clues may appear not in forgotten appointments but in persistent depression, unexplained emotional changes, declining attention or subtle alterations in behaviour years before diagnosis.
Not every episode of forgetfulness points to dementia, and not every mood disorder will progress to cognitive decline. Yet recognising these warning signs early provides an opportunity to identify reversible conditions, improve mental wellbeing and potentially delay future cognitive impairment.
As research continues to unravel how dementia develops, one message is becoming increasingly clear: protecting the brain is not something that begins in our seventies or eighties. It begins in mid-life—through caring for our mental health, staying physically active, managing chronic illnesses and keeping both the body and the mind engaged.
The greatest opportunity to fight dementia may come long before memory begins to fade.
