Humans have adapted to desire and rely on social connection. When deprived of this, people experience loneliness, a complex and unpleasant emotional response that works as a psychological mechanism to drive people to connect socially.

But new research appears to show that loneliness can literally kill, and some people face a higher risk than others.

Loneliness linked to poor mental health

Psychologist John Cacioppo of the University of Chicago performed a series of novel studies which yielded surprising results on the effect of loneliness on individuals. Loneliness has been linked to depression, and is thus a risk factor for suicide and substance abuse. Last year, it was reported that the proportion of suicides from among the elderly rose to 30%.

The results of a 2014 study by the Ministry of Social and Family Development and led by associate professor Angelique Chan of the Duke-NUS Graduate Medical School indicate that about 32% of older Singaporeans aged 60 and older report being sometimes lonely, and 19% report being mostly lonely. In addition, feeling lonely raised one's risk of dying by 34% over a four-year period, compared with those who were not lonely.

The social interaction lonely people do have are not as positive as those of other people, hence the relationships they have do not buffer them from stress as relationships normally should. Such stress may contribute to poor sleep quality which adversely affects wellbeing, as sleep is necessary for the body to repair itself physically and regulate mental states.

As such, lonely individuals report higher levels of perceived stress even when exposed to the same stressors as non-lonely people, and even when they are relaxing.

Increased risk of heart disease, infections and stroke

Loneliness also causes adverse physiological effects. Negative emotions, such as loneliness and depression, can increase the chances of infection, heart attack or stroke, states Duke-NUS Graduate Medical School dean K. Ranga Krishnan.

“Your entire body reacts when you feel down. When you feel lonely, you may not want to take medicine or take good care of yourself,” he explains.

To exacerbate things, in a survey conducted by Cacioppo, doctors themselves confided that they provide better or more complete medical care to patients who have supportive families and are not socially isolated.

In Singapore, loneliness tied to early death

In fact, the study led by Prof Chan found that loneliness significantly increases the risk of earlier death among Singapore’s elderly. In 2009, she and a team of researchers started tracking 5,000 Singaporeans aged 60 and older.

Through face-to-face interviews, information was gathered on their physical and mental health, family relationships, living arrangements and social networks. Questions such as how often they felt a lack of companionship or felt isolated from others were asked.

Two years later, the seniors were re-visited and it was found that 447 had died. The data showed that those who said they were lonely in 2009 were more likely to have died by the end of 2011.

More lonely men than lonely women

More men than women in the research had said they were lonely. Tsao Foundation’s Hua Mei Centre for Successful Ageing director Peh Kim Choo suggests that this could be because men tend to find it harder to share their feelings.

Men also usually build their lives and identities around their jobs and their role as the family’s breadwinner, so that they may feel lost and alone when they retire.

Living arrangements also had no effect on life expectancy – with the implication being that it is not about having people near, but the degree of connection one feels with another that affects loneliness.

People do not feel loneliness the same way

Last month, researchers at University of California San Diego School of Medicine published findings for the first genome-wide association study in loneliness as a lifelong trait, involving more than 10,000 people aged 50 years and older.

Led by Abraham Palmer, a professor of psychiatry, the results showed that despite a partial genetic factor (that possibly affects personality), environment plays a bigger role in affecting one’s tendency to feel lonely.

Being alone does not always equate to being lonely, and people do not perceive loneliness in the same way.

"For two people with the same number of close friends and family, one might see their social structure as adequate while the other doesn't," Palmer said. "And that's what we mean by 'genetic predisposition to loneliness'—we want to know why, genetically speaking, one person is more likely than another to feel lonely, even in the same situation."

After accounting for gender, age and marital status, it was found that the tendency to feel lonely over a lifetime, has a 14% to 27% genetic cause, and tends to be inherited together with neuroticism and depressive symptoms.

Healthcare professionals are just as vulnerable

Many external factors contribute to loneliness, and most of these are applicable to healthcare professionals. Loneliness is more likely among those who are unmarried or divorced. It has long been speculated that healthcare professionals are more likely to be divorced due to the long hours they keep and the stress associated with the job.

The results of a 2015 survey of more than 240,000 healthcare professionals found that the probability of being divorced was 25% among dentists, 31% among healthcare executives, 24% among physicians and 33% among nurses. There is no reason to think that the effect of long working hours does not extend to social relationships in general. MIMS

Read more:
Type 2 diabetes risk linked to marital status and long naps
Marriage found to lower senior’s mortality rates
Introversion and conscientiousness linked to poorer immune system and weak GI tract

Sources:
https://www.verywell.com/loneliness-causes-effects-and-treatments-2795749
https://www.psychologytoday.com/articles/200307/the-dangers-loneliness
http://www.huffingtonpost.com/dr-leeat-granek/loneliness-can-kill-liter_b_7031340.html
http://medicalxpress.com/news/2016-09-genes-lonely-loneliness-heritable-trait.html
http://www.livescience.com/18800-loneliness-health-problems.html
http://blogs.psychcentral.com/emotionally-sensitive/2012/03/loneliness/
http://www.charminghealth.com/applicability/loneliness.htm
https://hms.harvard.edu/news/doctors-and-divorce
http://www.healthxchange.com.sg/News/Pages/Loneliness-Shortens-Lifespan-Elderly.aspx