Loneliness can affect anyone, with millions feeling they have no one to turn to. Government statistics show that 47% of the British population - around 25 million people - feel lonely, with 6% stating they feel lonely often or always.
While there's no single cause and no one solution for loneliness, there are steps we can take to help ourselves and others.
Risk factors for loneliness can include being widowed, being unemployed, living alone, having a long-term health condition or disability, being between 16 and 24-years old, being from an ethnic minority community, being LGBTQ+, and more.
While the toll on our mental health is known, loneliness can also affect us physically, with studies suggesting it may have the same effect as smoking 15 cigarettes a day. Unfortunately, the stigma of loneliness makes it hard to talk about, which makes it worse. But there is no shame in feeling lonely.
What does loneliness look like?
"It’s not easy to spot someone who is lonely," Dr Kalpa Kharicha, head of research, policy and practice at the Campaign to End Loneliness, told Yahoo UK. "They’re not visible when you see someone on the street.
"No one wants to be known as a lonely person. They wear a mask because you want to present yourself in a certain way."
While it can be tricky to spot, certain groups of people are more vulnerable. "Living on your own, the bereaved, those in poor health that stops them getting outdoors, caring for somebody because it reduces your ability to look after your networks, people who’ve moved away," Dr Kharicha said. "These are all triggers."
Older people are also affected, with more than two million people in England over the age of 75 living alone, and more than a million older people saying they go for over a month without speaking to a friend, neighbour or family member, according to Age UK.
However, it's still important to remember that 'loneliness' and 'social isolation' are two different things.
The difference between depression and loneliness
Depression and loneliness are also separate issues but can go hand-in-hand, with one often triggering the other, Dr Kharicha said.
The mental-health disorder can be easier to spot, with a set of recognised symptoms. Depressed people often turn down social gatherings and avoid activities they once enjoyed, according to the charity Mind.
Some may also struggle to speak, think clearly or make decisions. Many are turned off sex and rely on cigarettes or alcohol to get through the day.
Others are constantly exhausted, move slowly, and even complain of constipation or unexplained aches and pains. Eating too much or little, leading to weight gain or loss, should also raise alarm bells.
How to help someone battling loneliness
Loneliness is serious, being linked to everything from dementia and heart disease to even an early death. You don’t have to feel helpless if you suspect someone is struggling, with even small gestures going a long way.
"Make small talk, offer a cup of tea to someone on your street, make conversation while waiting for the bus," says Dr Kharicha.
While it may not sound like much, a small act of kindness can make a big difference to someone who feels alone. "It shows openness," Dr Kharicha said. "Small gestures, listening and talking, can be very meaningful."
When it comes to older people, the NHS recommends offering to lend a hand, whether it be picking up prescriptions, changing a light bulb or giving them a lift to a doctor’s appointment.
With many struggling to cook for themselves, if possible, you could also take them over some hot dinner or some frozen leftovers for them to reheat, the health service adds.
Encouraging people to take part in activities in their local area can also help, whether it be volunteering, joining a book club or singing in a choir. "Anything that strengthens connection in communities," Dr Kharicha adds.
If that feels too much, just making an effort to catch up with someone over a drink, or on a walk, can have a big impact.
While many of us are glued to our phones, and have relied on technology for the past couple of years to stay connected, Kharicha stressed the importance of meeting up in the flesh where possible.
If you are struggling, the Samaritans are available 24/7 on 116 123.
Watch: 5 top tips to boost your mental health