Feeling lonely is all in the mind – right? It's not what you'd choose, but it's just one of those things and life goes on, regardless.

Wrong. More and more research is showing that feelings of loneliness transfer to your body and your brain, with disastrous results. Being chronically lonely can take years off your life.

Social psychologist John Cacioppo at the University of Chicago is a world leader in the biomedical effects of loneliness. In January this year he presented some of his latest research at the Society for Personality and Social Psychology meeting in San Diego.

His findings confirm a growing body of science showing that loneliness is more damaging than smoking 15 cigarettes a day, or being obese, or not taking exercise.

Lonely people have higher rates of cancer, infection and heart disease. In fact, they suffer from higher rates of 'all cause mortality', meaning all kinds of death from a range of causes. One is dementia – feelings of loneliness cause a 64 per cent increased risk of developing it.

Loneliness can cause dangerously high blood pressure because it raises levels of the stress hormone cortisol: the heart muscle has to work harder and arteries harden.

Even sleep is affected. It no longer 'knits up the ravelled sleeve of care', as Shakespeare puts it in Macbeth. Less time in bed is spent actually sleeping, sufferers wake up more at night, and sleep is less restorative, physically and psychologically.

It can get worse – already feeling bad, people can rate their own social interactions in a poor light and form negative impressions of people they meet. So they withdraw even further.

Even fruit flies that are isolated have worse health and die sooner than those that interact with others, showing that social engagement may be hard-wired, Professor Cacioppio said.

He is right, because the Scriptures show that God designed human beings for relationship with one another. From the beginning, it was 'not good for man to be alone'. When Romania was liberated from dictator Ceausescu in 1989 it was discovered that hundreds of babies in the appalling orphanages had died not from lack of food or physical care, but because of lack of human emotional connection, that is, from intense loneliness.

So what's the answer? Two of the best ways are said to be training people in the social skills they need to view the world in a more positive light, and to bring people together to share good times.

As a cognitive behavioural therapist, 'training' people to view the world in a more positive light seems a good option whatever the context, but in my work with the Pilgrims' Friend Society, a Christian charity that exists to support older people, I've found that loneliness is often the result of being isolated physically, either due to mobility issues or because friends and family have moved away. Some older people simply outlive their close connections.

But there is good news. It's the sort that, for me, confirms the truth of Philippians 2:13 – 'For it is God who is at work in you, both to will and to work for his good pleasure.' I believe that God longs to see human life working the way he designed it. My colleagues and I lead workshops and training days on issues of old age and are finding more and more churches keen to help lonely people.

Before a conference in South Wales last year we sent a list of proposed seminar topics to around 300 churches in the region, asking them to tick three that would be their top priorities. There was an unusually high return, around 40 per cent, and to my surprise, top of the list was 'loneliness' (dementia was second).

Loneliness in South Wales! The Welsh valleys are noted for a number of things, good and bad, but there's always been strong social cohesion. When I came back to Wales after years living abroad and in England I had to get used again to the way complete strangers would speak to you quite spontaneously. My daughter was amazed when, going over directions with me at a petrol filling station a man at the next pump interjected that our destination was just up the road and take the next right turn. I could never have imagined that there would be loneliness here. But there is. 

Under its 'Campaign to End Loneliness', Age UK has published a leaflet that churches will find helpful. There are also good ideas here.

Louise Morse is a cognitive behavioural therapist and writes on issues of old age. Her new book, What's Age Got To Do With It? will be released in September. She is also communications manager with the Pilgrims' Friend Society, a 210 year old Christian charity that supports older people.