Wednesday, 12 November 2014

Loneliness is a disease that changes the brain's structure and function

Loneliness increases the risk of poor sleep, higher blood pressure, cognitive and immune decline, depression, and ultimately an earlier death. Why? The traditional explanation is that lonely people lack life’s advisors: people who encourage healthy behaviours and curb unhealthy ones. If so, we should invest in pamphlets, adverts and GP advice: ignorance is the true disease, loneliness just a symptom.

But this can’t be the full story. Introverts with small networks aren’t at especial health risk, and people with an objectively full social life can feel lonely and suffer the consequences. A new review argues that for the 800,000 UK citizens who experience it all or most of the time, loneliness itself is the disease: it directly alters our perception, our thoughts, and the very structure and chemistry of our brains. The authors – loneliness expert John Cacioppo, his wife Stephanie Cacioppo, and their colleague John Capitanio – build their case on psychological and neuroscientific research, together with animal studies that help show loneliness really is the cause, not just the consequence, of various mental and physical effects.

The review suggests lonely people are sensitive to negative social outcomes and accordingly their responses in social settings are dampened. We know the former from reaction time tasks involving negative social words (lonely people respond faster), and tasks involving the detection of concealed pain in faces (lonely people are extra sensitive when the faces are dislikeable). Functional imaging evidence also shows lonely people have a suppressed neural response to rewarding social stimuli, which reduces their excitement about possible social contact; they also have dampened activity in brain areas involved in predicting what others are thinking – possibly a defence mechanism based on the idea that it’s better not to know. All this adds up to what the authors characterise as a social "self-preservation mode."

Meanwhile, animal models are helping us to understand the deeper, biological correlates associated with loneliness. For mice, being raised in isolation depletes key neurosteroids including one involved in aggression; it reduces brain myelination, which is vital to brain plasticity and may account for the social withdrawal and inflexibility seen in isolated animals; and it can influence gene expression linked to anxious behaviours.

What about changes to our neural tissue? Human research is suggestive: in one study, people who self-identified as lonelier were more likely to develop dementia. Here, initial cognitive decline could be causing loneliness, but animal work gives us some plausible mechanisms for loneliness’ impact: animals kept in isolation have suppressed growth of new neurons in areas relating to communication and memory, just as very social periods such as breeding season see a pronounced spike in growth.

Other basic brain processes are also upset by isolation. Isolated mice show reduced delta-wave activity during deep sleep; and their inflammatory responses also change, meaning that in one study, three in five isolated mice died following an induced stroke, whereas every one of their cage-sharing peers survived the same process.

The research is clear that loneliness directly impacts health, so we need to do what we can to help people free themselves from social marginalisation. I’ve seen one approach during my time serving with time banking charities, in which people give their own time in return for someone else’s in a different situation – a process that can build social networks. Also the issue is acquiring momentum through the Campaign to End Loneliness and technology solutions such as the RSA’s Social Mirror project – an app that tells people about local social groups and activities. Mainstream health is also picking this up under the term “social prescription” (physicians advise patients of social groups and activities and “facilitators” help the patients take up the opportunities). But amongst all the institutional activity, we mustn’t forget our individual duties: sometimes all that’s needed is to reach out.


Cacioppo, S., Capitanio, J., & Cacioppo, J. (2014). Toward a neurology of loneliness. Psychological Bulletin, 140 (6), 1464-1504 DOI: 10.1037/a0037618

Post written by Alex Fradera (@alexfradera) for the BPS Research Digest.


  1. Since the woman is first author, she should be mentioned first in your article, the expert can be second, possibly identified as that (see below), and identified as her husband, if their marital relationship is relevant to the point of the article. And above all, she should be given the respect of her full name, even though it means, in the current order, repeating their shared last name. If for some reason your style book says you never repeat last names that are the same, then in the order I propose, you would call him "John, loneliness expert." Also, I find myself wondering why the primary author doesn't merit being called an expert. In fact, the "expert is the last author on the paper. Author order has meaning.

    That said, I want to say how much I appreciate the information service you provide.

  2. Thanks for raising this point. Prior to publication of the post, Alex and I (the editor) discussed how best to present the names of the authors in this paper. Usually our house style is to only mention the first author or most senior author (the two are not always the same), but in this case we especially wanted to highlight that John Cacioppo was involved because he is a (or even "the") world authority on the subject of loneliness and its psychological and neurological sequelae. This seemed to us highly relevant to the trustworthiness of the review (were the review focused on love and desire, we would have wanted to highlight the authorship of Stephanie Cacioppo, whose publication record was, until recently, more focused on these topics). Anticipating the very objections you have raised, we chose to depart from usual Digest convention and to mention all the authors involved in the study, and to include a weblink to each of their respective web pages. To repeat the Cacioppo surname seemed redundant, especially given the full names in the reference at the bottom of the post. However, given this omission has unfortunately been interpreted as derogation or disrespect, I have happily inserted Stephanie's surname. The marital status of two of the authors was judged to be a point of human interest, and Alex and I noted that the pair have several times spoken in the media about their personal and working relationship.

  3. A good strategy to reduce drinking amongst men? Over the long-term, change the cultural attitudes to women and gay men; over the short-term, point out that it tends to make it difficult to get an erection, and is implicated in heart disease, which itself manifests early on as erectile dysfunction.

  4. Although the conclusion seems clear: we should reach out, it is not as simple as that. People who feel lonely are usually not capable of reacting in a positive way to such invitations. Partly bacause they often lack the skills to do so, but also because they do not experience positive outcomes from being social.
    We really need more people who are educated in dealing with loneliness. People who feel lonely need help just as much as peoiple who suffer from other life threatening causes. Real help. From people who know thier business.

  5. I feel there should
    be 2 ways of looking at loneliness – one
    is group people who prefer to be lone,
    though they have all facilities to be otherwise. Here the
    brain might have already been changed in its structure to such
    a level that further
    usage or over usage of ones’ cognitive abilities are going to be a burden to their system. They prefer
    to be alone, talking/seeing/sensing less and less. Here
    loneliness is a symptom than a cause. The other group choose to be alone, due to a crisis in their life. They have
    normal brain functions, and long periods of loneliness could change brain
    structure. To bring them back to normalcy could be relatively easy,
    provided a non dominating friend/counselor put little effort to bring back the loner confident and agile.

  6. I think you are mixing being lonely and being alone. If someone likes being on his/her own, it's silly to think that it's not "normal" and that it should be changed.

  7. At first, I found it shocking that loneliness has
    such an immense and direct impact on health. I can now see, though, that the
    importance of socialization is extremely high as it can encourage sound sleep,
    lower blood pressure, increase cognitive and immune activity, decrease
    depression, and help people live longer, healthier lives. During my studies in
    Psychology 101, I have learned about how loneliness and sociability can, in specific, affect frequency of
    sicknesses and rate of recovery. Pittsburg Carnegie Mellon University students were
    used to study this by participating in an experiment which first injected them
    with the flu virus. After being injected, the students were asked questions
    about their social interactions. Following this study, Sheldon Cohen of
    Carnegie Mellon University concluded that the people who are the loneliest
    produced the least amount of antibodies and the people who are the least lonely
    produce the most amount antibodies. Therefore, the rate of recovery for more
    social people is typically higher than that of less social people. With all
    this information in mind, I am persuaded to agree with the author of this
    article that organized outreaches should be established to encourage lonely
    people to become a part of a social group. At such social groups, hopefully
    lonely individuals can receive personal support as well as the health benefits
    that have been proven to come along side socialization. It is also very
    important, as the author states, to be actively reaching out to others on our
    own so that we can encourage social interaction thus discourage social

  8. Loneliness is a perception of the individual. If an individual perceives that they are lonely in a crowded room, social activities could perhaps cause more anxiety and heighten the feeling of being lonely. Loneliness is complex and unique to each individual. Just as in physical training, if one doesn't continue to exercise, they will lose the progress they have made. Loneliness correlates to social atrophy. If one doesn’t experience social interaction on a regular basis, then they are more likely to feel increasingly awkward on the infrequent occasions they engage with others. If there is a chemical imbalance contributing to the perception of social isolation that should be addressed as well.

  9. Has there been much psychological research on how people come to be lonely?

  10. "Meanwhile, animal models are helping us to understand the deeper, biological correlates associated with loneliness." But the unfortunate victims of this heartless investigation have to be "raised" by their human tormentors, in other words, they are obliged by external forces to expirience isolation - they would tell us more about the horrific effects of, for instance, the sort of solitary confinement issues so common in the US prison system, rather than social loneliness. Only humans seem to have this deep disconnect from their fellows - perhaps because they are capable of this sort of cruelty and lack of empathy? Cause, effect, or a bit of both?

  11. Contemporaneously, it is healthier to avoid contact with humans, given the Moral Evolution level that most of humanity reaches, it was said on inversion of values but is the correct default values: Sacrificing innocent animals in 'research' but sustain human criminals healthy that not need to work ... You who live in countries with serious advanced civilization can inquire about sociability, but for me living in Brazil where Football and Carnival is more important than Public Health, Education and Security, be antisocial is rule of survival: here, ride a car is status and bike is poor's thing, that is, not even -at least, think people around me can! In the Bible it is written 'Separate yourselves from evil' and yes, humans represent the evil, or I have to socialize: drink alcohol, fight with the opposing soccer fans, honk for seniors trying to cross the street, and have fun 'riding car' or going to rodeos, as the natives?

  12. I love being alone,people that constantly need others are the ones with the problem. There is a desperation about them. If you don't like your own company then why should others.The more you spend time alone the more you like it...bliss! Now boredom is another matter.

  13. absolutely nothing worse than people that need others to stop them feeling lonely, Dependency makes you vulnerable being with anyone to stop feeling lonely gets you involved with all sorts of unsuitable people.

  14. For me it's more that the husband is noted as the 'expert' (and not referred to by his marital status) and the woman is noted simply as 'his wife' that is an issue. For someone unfamiliar with their work (ie me) it was only the words 'their colleague' that let me know that the 'wife' was actually a researcher in her own right. This seems like a small niggle in an otherwise excellent article but, whereas I agree that their marital status is interesting, 'the expert's wife' falls a bit short of giving this author the credit she deserves.

  15. Something the article did not mention was the death of a person's mate or significant other is a large factor in becoming alone, thus feeling lonely. Also, aging and disability can make socializing painful and/or difficult to accomplish.

  16. Many that lose their partner/spouse spend the rest of their lives alone and complain of loneliness. I know because my partner died and my friends who lost partners and people from grief support say similar statements regarding being alone and lonely. I am disabled and I get lonely because I cannot do many activities because of pain and a spinal cord injury.

  17. Stephanie Cacioppo was not noted simply as "his wife". She was described, like her husband and her colleague, as an author of the paper. And her name also appears with her co-authors in the full reference given at the end of the post.


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