Social Relationships as Blockbuster Drugs

New research establishes that strong social relationships cause better health.

Posted Jun 10, 2019

...when you're smilin'...the whole world smiles with you.—Louis Armstrong

Tambako The Jaguar (Flickr)
Maternal attachment
Source: Tambako The Jaguar (Flickr)

In the 1960s, a group of scientists separated baby monkeys from their mothers for periods of several weeks. The baby monkeys screamed, scratched, and sucked on the wires of their cages. Eventually, they curled up into little balls and stopped moving. Many became ill and at least one died. In some of the experiments, the baby monkeys were reunited with their mothers and became happy again.

While much less dramatic than the monkey studies, research with millions of people has found a link between close connections to others (friends, family, and social groups) and longer life. People with "strong" connections (those who have a number of people they can count on) live an average of five years longer than those who aren’t. If this is correct, then being socially isolated is as bad for health as smoking

The further we are from friends, family, and loved ones, the worse it is for our physical and mental health

Why then, you might ask, aren’t there campaigns to promote stronger social relationships, the same way there are campaigns to reduce smoking? Well, there are some (see here for an example). And urban design is attempting to design cities in a way that combats loneliness. Yet the health benefits of social relationships are not being taken seriously enough: Studies report we’re getting lonelier, and that the hours we spend on social media get in the way of quality face-to-face time.

A reason why strong social relationships aren’t being treated seriously enough could be skepticism about the underlying evidence. The studies connecting better health to strong social relationships are epidemiological. One of the most famous recent epidemiological studies is the one that discovered a higher rate of lung cancer among smokers.

A problem with epidemiological studies is that they don’t tell us what the cause is. So the epidemiological studies linking relationships and health don’t tell us whether strong social relationships cause better health or vice versa.  After all, healthy people may be better at keeping up with friends or family. So it might be that being healthy causes better social relationships rather than the other way around. The easiest way to prove whether social relationships cause better health would be to do a randomized trial.

In theory, we could do this by taking a thousand or so people, flip a coin to select some that are told to not contact their friends or family for a while, then compare their health with those who were allowed to stay in touch with their friends and families. Such a study would be impossible, except maybe in an extraordinarily authoritarian state. Unless you live in a dictatorship, you can’t randomly control how many friends and family members people stay in touch with.

Early studies linking smoking with lung cancer faced the same problem: you can’t randomize people to smoke or not. So to prove that smoking caused lung cancer, scientists had to look beyond the epidemiological studies

Early studies linking smoking with lung cancer faced the same problem: you can’t randomize people to smoke or not. So to prove that smoking caused lung cancer, scientists had to look beyond the epidemiological evidence. In a recent study, we used the same strategy for the apparent link between social relationships and health.

First, we looked to see whether there was a mechanism linking social relationships and health. If we can explain why social relationships cause better health, then people are more likely to accept that one causes the other. In fact, there are two evidence-based ‘mechanisms’ that explain how stronger social relationships can improve health. The ‘main effect’ mechanism states that friends and family provide actual help. You might take a disabled friend for a walk, lend an ear to a brother who is feeling sad, or inform a relative with an illness about a new treatment. The other mechanism is the stress-buffering hypothesis, which states that social relationships can reduce stress. Reduced stress results in all the benefits of stress reduction. The biochemical pathways through which chronic stress adversely affects health include: hindering immune system function, detrimental volume reductions in prefrontal cortices, and increased inflammation. Having stronger social relationships reduces stress.

We also looked for experiments that were not epidemiological. Although randomized trials in humans aren’t possible, other types of experiments (that didn’t involve flipping a coin to choose whether someone should be separated from their friends and family) have been done. In the 1940s, some foster children were removed from sterile environments and given temporary mother carers. As a result, their IQs rose.

Taken together with the epidemiological evidence, these (and other) factors showed beyond any reasonable doubt, that strong social relationships cause better health. In fact, if good relationships were a drug, it would be a blockbuster. Here are three ways you can use it.

1. Join a group that interests you. Join a hiking, singing, chess, or cheese-tasting group. Other than groups which are clearly harmful (like violent gangs), any group will do.

2. (Re)connect with a family member. Invite them over for lunch, tea, or dinner, or just give them a call. If you don’t have any family members that you can connect with, opt for a friend, or even someone from the group you are about to join after reading number 1 above.

3. (My favorite) Do a random act of kindness. Random acts of kindness are small things you can do that make others happy and that at the same time connect you to them. See here for some cool examples. An easy one is to pay someone a compliment. Wish someone at the checkout counter a great day. Tell the waiter or waitress how much you appreciate their hard work. Tell the bus driver thank you for getting you to your destination safely. Compliment someone on their great parallel parking. Or easier: Just smile at someone.

We’re more like the screaming baby monkeys than we think: Our health suffers when we are less well-connected to our friends, family, and social groups. Unlike the baby monkeys, however, we have the power to strengthen our connections with friends, families, and social groups. Our good health depends on the little effort that takes.


1Holt-Lunstad J, Smith TB, Layton JB. Social relationships and mortality risk: a meta-analytic review. PLoS medicine2010;7(7):e1000316. doi: 10.1371/journal.pmed.1000316.

Holt-Lunstad J, Smith TB, Baker M, et al. Loneliness and social isolation as risk factors for mortality: a meta-analytic review. Perspectives on psychological science : a journal of the Association for Psychological Science2015;10(2):227-37. doi: 10.1177/1745691614568352.

Howick J, Kelly P, Kelly M. Establishing a causal link between social relationships and health using the Bradford Hill Guidelines. SSM Popul Health. 2019 Aug; 8: 100402. Published online 2019 May 4. doi: 10.1016/j.ssmph.2019.100402.