Leading brain specialists have warned that subtle personality changes in midlife could be among the earliest warning signs of dementia – often emerging years before memory problems are noticed.
Professor Gill Livingston, an expert in the psychiatry of older people at University College London (UCL), says shifts in behaviour, confidence and emotional responses are frequently reported by families long before a formal diagnosis is made.
Research she was involved in, tracking thousands of UK civil servants, found that changes in personality traits during midlife were linked to a higher risk of developing dementia later on.
It adds to mounting evidence that hidden damage to the brain in the early stages of the disease can alter how people think, feel and react long before more well-known symptoms become obvious.
Doctors say relatives often recall that the first signs were not forgetfulness, but changes in temperament – such as becoming anxious, impulsive, withdrawn or emotionally distant.
Professor Livingston and her colleagues have identified several shifts – which they termed depressive symptoms – that appear to raise concern when they represent a clear departure from someone’s long-standing behaviour.
While they cannot be used as definitive proof of dementia, they may, cumulatively, reveal a concerning pattern that warrants further investigation.
And, crucially, with up to 45 per cent of dementia cases thought to be linked to lifestyle factors – and therefore potentially preventable – catching the illness in its earliest stages may open the door to action to limit or slow decline, some experts hope.
Brain specialists have warned that subtle personality changes in midlife could be among the earliest warning signs of dementia – often emerging years before memory problems
The first change highlighted is a loss of confidence.
People who reported ‘losing confidence in myself’ as an issue in their 40s and 50s were significantly more likely to go on to develop dementia than those who did not.
This symptom emerged as the strongest single predictor among dozens examined, outperforming low mood, hopelessness and sleep problems.
Those who experienced a drop in self-confidence had around a 50 per cent higher risk of dementia, even after accounting for genetics, education, heart disease, lifestyle and other known risk factors.
Crucially, in people under 60, loss of confidence largely explained the long-observed link between midlife depression and dementia, suggesting it may reflect very early brain changes rather than a reaction to ageing or life stress alone.
Struggling to cope with everyday problems in midlife also stood out as a strong early signal.
People who reported feeling unable to face up to problems in their 40s and 50s were significantly more likely to develop dementia years later, suggesting that a reduced ability to manage stress can precede more obvious cognitive symptoms by decades.
Researchers believe this may reflect an early erosion of the brain’s ‘cognitive reserve’ – the mental capacity that allows people to juggle demands, adapt to pressure and recover from setbacks.
Everyone experiences dementia differently. Use this checklist to help you make a note of your symptoms before you talk to your GP.
As this reserve diminishes, situations that were once manageable can start to feel overwhelming, long before memory loss or confusion become apparent.
The study also found that people who reported ‘not feeling warmth and affection for others’ in midlife were at significantly increased risk of developing dementia later in life.
Affected individuals had a 44 per cent higher risk compared with those who did not report the symptom, which may manifest as emotional withdrawal or reduced conscientiousness.
Speaking to The Telegraph, dementia expert Professor Geir Selbaek of the University of Oslo said: ‘People who are very conscientious exercise more, avoid putting on weight, and have a lower risk of diseases such as diabetes and hypertension [which are also linked to dementia].’
Ongoing nervousness also emerged as a risk marker. People who described themselves as ‘nervous and strung-up all the time’ in midlife were more likely to develop dementia over the following decades.
This is a key sign of neuroticism, a personality trait strongly linked to dementia. Professor Selbaek believes chronic stress may play a role.
‘I think that is one of the mediating factors. Increased levels of stress lead to higher levels of inflammation in the body, and both are devastating for brain health.’
A persistent sense that tasks were not being carried out properly also emerged as an early signal. Participants who reported being ‘not satisfied with the way tasks are carried out’ in midlife were more likely to develop dementia years later.
Problems with concentration also featured. People who reported ‘difficulties concentrating’ in midlife were more likely to develop dementia later in life, placing impaired focus among the six specific depressive features linked to long-term risk.
Specialists stress that context matters. Personality changes can also be caused by life events, menopause, mental health issues or stress.
The key red flag is a clear change from someone’s usual way of coping, rather than a pattern they have shown before.
Lifestyle steps such as staying socially engaged, maintaining routines, managing stress, exercising regularly and treating depression may help reduce long-term risk – even if brain changes have already begun.