Ireland, famous for its friendliness, is showing a striking social shift, with increased feelings of loneliness and worsening social support among our youngest adults. While COVID may have influenced this trend, the first OECD report on social connection shows that daily face-to-face interactions have been falling consistently since 2006 while remote contact has increased. In Ireland, CSO figures show that in 2024, 5.6 per cent of 16- to 24-year-olds said they felt lonely “most or all of the time”. This is approximately 80 per cent higher than those aged 65+ (3.1 per cent). In a country built on conversation, it is our youngest adults who now feel the most disconnected – a reversal that carries profound implications for brain health.
Connection nurtures and nourishes the brain. Social interaction activates reward, memory and emotion networks, promoting neuroplasticity – the brain’s ability to form and strengthen connections which is fundamental to brain health. Every conversation, shared meal or laugh with a friend gives the brain a workout, engaging multiple systems at once.
When we become isolated, those systems start to weaken. Over time, loneliness reshapes the brain: empathy declines, trust diminishes and the regions responsible for social understanding lose efficiency. The brain quite literally begins to protect itself by withdrawing – but that self-protection comes at a cost.
Loneliness, in small doses, is adaptive. It motivates us to seek connection. But when ignored, it becomes toxic, interfering with sleep, suppressing immunity and increasing cortisol levels. The brain, in self-preservation mode, scans for danger and misreads social cues. The lonelier we feel, the harder it becomes to reach out, creating a spiral of isolation and physiological stress that accelerates brain ageing.
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The link between loneliness and dementia risk is now firmly established. Persistent loneliness and social isolation increase the likelihood of developing dementia, with an effect size comparable to smoking, physical inactivity or high blood pressure. People with more social ties are less likely to experience cognitive decline, while those who remain socially engaged show slower loss of brain volume and stronger neural networks.
Social activity is like cognitive training – effective, enjoyable exercise for the brain. It keeps the brain active, builds brain resilience and supports the growth of new neurons.
But the relationship is not one-way. Early brain changes associated with Alzheimer’s can also lead to social withdrawal. People in the very earliest stages may lose confidence, misread social signals or find conversation exhausting. That makes it harder to tell which came first – the loneliness or the cognitive decline. In truth, both processes likely feed each other through shared biological pathways: chronic stress, inflammation, impaired sleep and reduced levels of brain-derived neurotrophic factor (a key growth hormone that promotes neuroplasticity).
The takeaway is clear: addressing loneliness has no downside. It can reduce dementia risk and protect mental, physical and brain health.
We often treat loneliness as a late life issue, but brain ageing begins much earlier than most people realise. From around age 30, brain volume declines. How quickly that happens depends largely on lifestyle – physical activity, social connection, mental stimulation, quality sleep and a healthy heart, diet and weight help maintain brain volume.
The latest Lancet Commission on Dementia Prevention published in 2024 identifies 14 modifiable risk factors including social isolation and hearing loss. Up to 45 per cent of dementia cases could be prevented or delayed by addressing these throughout life. Brain health is not something to look after later. It’s something we build, or neglect, every day of our lives.
If loneliness is rising in younger generations, we must ask why. They lived through the social disruptions of COVID, housing insecurity, remote work and a digital culture that prizes constant availability over genuine intimacy. Many maintain hundreds of online contacts yet struggle to identify a single person they can rely on for social support. Connection isn’t the same as contact. These early patterns of digital dependency and social avoidance could lay the neural groundwork for later isolation – the kind that increases risk for both depression and dementia.
Technology can help us stay in touch, but heavy, compulsive use can make loneliness worse. The problem isn’t the phone itself but how it’s used. Constant scrolling can displace in-person interaction, disrupt sleep and fragment attention – all of which impair memory and mood. Social media can trick the brain into thinking we’re socially satisfied when in fact we’re starved of social support and crave social contact. Ideally, digital connection should lead back to human contact – not substitute for it.
Earbuds and headphones can create a comforting cocoon, but may act as a barrier to social connection. When we seal ourselves off from the sounds around us, the chatter in a cafe, the birds on a walk, we lose the chance for spontaneous social interaction. Over time, listening at high volumes can also damage hearing, and that loss doesn’t just silence the world; it increases isolation and, in turn, raises dementia risk.
We tend to associate hearing loss with ageing, yet it is increasingly a problem among younger people. Long-term exposure to loud music, concerts, earbuds and gaming headsets is taking its toll. Hidden hearing loss often goes unnoticed at first, but it makes conversation effortful, leading to withdrawal, fear, fatigue and frustration – the first steps towards isolation.
Hearing loss is one of the largest modifiable midlife risk factors for dementia. It likely contributes through three pathways: increased cognitive load (the brain working harder to decode sound), reduced auditory stimulation (accelerates atrophy in sound-processing regions) and social withdrawal (less conversation, less engagement, less stimulation, increased depression). Instead of acting on the unpleasant feeling of loneliness, we often try to mask or dull it with alcohol or unhealthy eating habits, which also increase dementia risk. Protecting hearing protects cognition.
Keep headphone volume below 60 per cent and limit listening to 60 minutes at a time. Wear ear defenders if using loud machinery or tools. Have your hearing checked regularly. Early intervention matters. Studies show that treating acquired hearing loss with hearing aids can slow cognitive decline in at-risk older adults. The message for younger people is prevention.
Loneliness, whether in youth or old age, is not a personal failing. It’s a biological signal that we’ve drifted too far from our social group. Ignoring it endangers not just mood, but brain health.
Feeling lonely just means you are human – but staying lonely can make you ill, change your behaviour and change your brain. Connection nurtures and nourishes the brain. It builds resilience, maintains memory and empathy, and may be one of the simplest, most powerful ways we can protect ourselves against cognitive decline.
Ireland’s challenge is to treat social connection as essential infrastructure, not a luxury. That means supporting befriending services, community spaces, providing opportunities to meet across generations – and teaching people of all ages that connection, conversation and care are as vital to their future brains as sleep or exercise.
Dr Sabina Brennan is a psychologist and neuroscientist. She is the author of four Irish Times best-sellers including Still Me – A Neuroscientist’s Guide to Caring
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