Loneliness can shorten your life, a new study has shown.
Scientists in the US found that "feeling lonely" almost doubled the risk of dying in a population of 1,600 older individuals.
Loneliness was also associated with functional decline and a reduction in day-to-day activities.
Participants in the study, who had an average age of 71, were asked if they felt "left out", isolated or lacking in companionship.
Around 43% met the researchers' definition of loneliness, which was experiencing one of these states at least some of the time.
The authors, led by Carla Perissinotto, from the University of California at San Francisco, wrote in the online journal Archives of Internal Medicine: "Loneliness is a common source of suffering in older persons. We demonstrate that it is also a risk factor for poor health outcomes including death and multiple measures of functional decline."
A separate US study in the same journal found a link between living alone and an increased risk of death from heart disease among people at risk of blood clots.
Scientists examined data on 44,573 middle-aged participants, 8,594 of whom lived alone.
Living alone was associated with 3% greater chance of dying over a period of four years. It also increased the risk of death from heart disease from around 7% to 8.6%.
What is loneliness?
According to MIND: "To feel lonely is to be overwhelmed by an unbearable feeling of separateness, at a very deep level. To some degree, it is a totally normal emotion, a part of growing up.
"At birth, we all start the process of separation, the growth towards becoming individuals. Also, from our earliest months, as awareness of our separateness dawns upon us, the parallel need to seek relationship begins.
"It's a balancing act, a see-sawing between the search for intimacy and an acceptance of isolation that continues throughout life.
"However smoothly this passage from birth to mature adulthood goes, there are bound to be times in our lives when this process of growing up, of becoming separate selves, feels difficult; times when we feel anxious, abandoned, unloved, insecure. In other words, when we feel lonely."