Where does loneliness come from? It may be in your genes

Produced by: Science Popularization China

Author: Denovo Team

Producer: China Science Expo

Do you often feel lonely?

A scientific study published in 2018 showed that in developed countries, about one-third of the population is affected by the negative emotions brought about by loneliness, and one-twelve of them are severely affected.

Although we live in the most socially connected era in human history, many people still feel lonely. It is worth noting that loneliness is not the same as enjoying solitude or avoiding social activities . We can be alone without feeling lonely, or we can feel lonely in a group of people. Loneliness is an extremely subjective and personal feeling. Only when you feel lonely, you are truly lonely .

The three loneliest moments in life

In academic research on loneliness, the three loneliest moments are not going to an amusement park alone, moving alone, or having surgery alone, but three stages of life.

Dilip Jeste, a geriatric neuropsychiatrist at the University of California, San Diego, and his research team conducted a mental health assessment of 340 San Diego residents aged 27 to 101. The results showed that loneliness is most severe in people in their 20s, 50s and 80s.

While the data did not provide conclusive evidence to explain why loneliness peaked in these age groups, the researchers speculated that it may be related to life challenges and stressors that are common during these specific age groups.

UC San Diego study on the relationship between wisdom and loneliness

(Image source: Cerebral Cortex magazine)

The twenties are often a time of critical decision making in a person's career, and the pressure often comes from seeing peers seemingly making better choices than themselves , which in turn leads to guilt and self-doubt.

The fifties are often a period when midlife crisis and health issues are intertwined , which may lead to deeper thinking about death.

In one’s eighties, the psychological toll can reach new highs, or more accurately, new emotional lows— due to physical decline, the possible onset of illnesses such as dementia, and the death of loved ones.

(Photo source: veer photo gallery)

Loneliness is common in all age groups. Please be prepared to face challenges in the above three age groups. Perhaps you will really feel more lonely at that time.

The feeling of loneliness is inherent in our genes!

Although it is generally believed that loneliness is mainly influenced by the surrounding environment and life experiences, a 2018 scientific study revealed that the degree of loneliness we feel, or how often we want to socialize, may be determined to some extent by our genes .

In the UK Biobank, a large-scale biomedical database in the UK, there is a comprehensive survey data of 487,647 participants, based on which researchers identified 15 genetic regions associated with loneliness.

(Photo source: veer photo gallery)

While these genetic genes cannot fully guarantee or completely rule out loneliness in an individual (as this is a complex phenomenon involving multiple genetic and environmental factors), the data collected does provide strong evidence for a link between loneliness and genetics.

According to statistics, the genetic tendency of loneliness is about 4-5% . This means that two people in very similar environments and situations may have different feelings about loneliness - this difference may be attributed to their different genes .

In another study, researchers at the University of California, San Diego School of Medicine looked at genetic information from 10,760 people aged 50 and older and asked participants three well-known questions to measure loneliness: How often do you feel that you lack companionship? How often do you feel left out? How often do you feel isolated from others? This was to determine how often participants felt lonely .

Genetic correlations between loneliness and other traits: personality traits (neuroticism, extraversion), psychiatric disorders (schizophrenia (SCZ), bipolar disorder (BP), and major depressive disorder (MDD)), the Depressive Symptoms Scale (DS), and height.

(Image source: Reference [3])

By matching the genetic information with the questionnaire results, the researchers estimated that genetic inheritance accounts for 14% to 27% of an individual's loneliness.

In summary, loneliness is a very subjective experience, but our genes can determine how strongly we feel it and how often we experience it.

Lonely people think differently

The UCLA research team conducted a study involving 66 first-year college students aged 18 to 21. The participants were first asked to complete a detailed questionnaire to assess whether they experienced loneliness in their daily lives.

Then, using functional magnetic resonance imaging (fMRI), the scientists observed the students' brain activity as they watched 14 different video clips.

Based on the responses to the questionnaire, the participants were divided into two groups: "lonely" and "non-lonely." When the researchers analyzed the fMRI imaging data, they found that the brain activity patterns of lonely people were significantly different from those of non-lonely people.

(a) Schematic diagram of the study paradigm. Participants entered a laboratory session where their brain activity was measured using fMRI while they watched a series of videos. After completing the fMRI scan, participants completed a questionnaire.

(b) Schematic diagram of the analysis. Time series of neural responses to the videos were extracted for each of the 214 brain regions, and these time series were then correlated across participants to compute the between-subject correlation for each bigram in each brain region.

(Image source: Reference [4])

What is more noteworthy is that even within the "lonely" group, individuals' brain activity showed significant differences, while the brain activity of the "non-lonely" group was relatively consistent.

The findings reveal a fascinating phenomenon: lonely people's brains process information from the outside world differently than their peers. This lack of understanding may be a key factor in their feeling of disconnection from others.

Although it is not yet clear whether this unique way of processing information is a cause or consequence of loneliness, this difference clearly makes it more challenging for lonely people to establish social connections with others, lonely and non-lonely alike.

Of course, the brain is one of the most complex organs in the human body. Different people’s brains work differently, but neither is good or bad. Understanding how the brains of lonely and non-lonely people work simply deepens our understanding of loneliness, a complex psychological phenomenon, and provides valuable information for further research.

Lonely people, you are different, but that doesn’t mean you are bad.

Loneliness: An invisible health crisis

Numerous studies have clearly shown that chronic loneliness (rather than enjoying it) can pose a significant threat to physical and mental health, with a range of disturbing effects at the biological, psychological and even social levels.

From a biological perspective , long-term loneliness can lead to accelerated aging, increased cancer lethality, weakened immunity, and even an increased risk of Alzheimer's disease. The dangerous effects of loneliness are comparable to smoking 15 cigarettes a day or drinking 6 glasses of wine a day.

Even more worrying is that once loneliness becomes a long-term state, it may trigger a self-protection mechanism that makes people more closed and defensive. Because the brain sees social pain as a threat as physical pain, long-term loneliness may cause people to be in a constant state of high alert, feeling threatened and hostile everywhere.

If you suffer from chronic loneliness, the first thing to do is to recognize and break the cycle.

Unhealthy experiences of loneliness may lead to negative emotions and make one unwilling to connect with the outside world too much, further exacerbating this unhealthy feeling of loneliness.

To break this cycle, you need to start by changing your attention, worldview, and behavior.

(Photo source: veer photo gallery)

If it is difficult to change on your own, you may want to seek help from a professional mental health professional or organization.

Research shows that improving the quality of your relationships, especially building deeper and more meaningful relationships, is also an effective way to address loneliness.

Tackling loneliness requires self-awareness, professional help, and a scientific approach. Each step is a step toward a healthier social life and a better self.

Conclusion

Whether from the perspective of individual psychology or as a public health issue, loneliness should receive greater attention.

We do not deny that in today's high-density and high-intensity social connections, individuals will choose to be alone and relax themselves in order to escape social pressure and gain temporary inner peace, which in itself is beneficial to physical and mental health.

However, unhealthy feelings of loneliness do carry risks to one’s physical and mental health. Just as most animals derive what they need from their natural environment, we humans extract the emotional and psychological support we need from high-quality social interactions and use this as a foundation to build and maintain our social structures.

References:

[1]Lee, E., Depp, C., Palmer, B., Glorioso, D., Daly, R., Liu, J., et al. (2019). High prevalence and adverse health effects of loneliness in community-dwelling adults across the lifespan: Role of wisdom as a protective factor. International Psychogeriatrics, 31(10), 1447-1462.

[2]Day, FR, Ong, KK & Perry, JRB Elucidating the genetic basis of social interaction and isolation. Nat Commun 9, 2457 (2018).

[3]Gao, J., Davis, L., Hart, A. et al. Genome-Wide Association Study of Loneliness Demonstrates a Role for Common Variation. Neuropsychopharmacol 42, 811–821 (2017).

[4]Baek, EC, Hyon, R., López, K., Du, M., Porter, MA, & Parkinson, C. (2023). Lonely Individuals Process the World in Idiosyncratic Ways. Psychological Science, 34(6), 683–695.

[5]Our Epidemic of Loneliness and Isolation(2023). The US Surgeon General's Advisory on the Healing Effects of Social Connection and Community

[6]Cacioppo JT, Cacioppo S. The growing problem of loneliness. Lancet2018;391:426. doi:10.1016/S0140-6736(18)30142-9.