COVID-19: loneliness epidemic – How does your brain process emotions?


Research over the last decade has shown that loneliness is an important determinant of health. It is associated with considerable physical and mental health risks and increased mortality.

Previous studies have also shown that wisdom could serve as a protective factor against loneliness. This inverse relationship between loneliness and wisdom may be based in different brain processes.

In a study published in the March 5, 2021 online edition of Cerebral Cortex, researchers at University of California San Diego School of Medicine found that specific regions of the brain respond to emotional stimuli related to loneliness and wisdom in opposing ways.

We were interested in how loneliness and wisdom relate to emotional biases, meaning how we respond to different positive and negative emotions,” said Jyoti Mishra, Ph.D., senior author of the study, director of the NEATLabs and assistant professor in the Department of Psychiatry at UC San Diego School of Medicine.

The study involved 147 participants, ages 18 to 85. The subjects performed a simple cognitive task of determining which direction an arrow was pointed while faces with different emotions were presented in the background.

“We found that when faces emoting anger were presented as distractors, they significantly slowed simple cognitive responses in lonelier individuals. This meant that lonelier individuals paid more attention to threatening stimuli, such as the angry faces.”

“For wisdom, on the other hand, we found a significant positive relationship for response speeds when faces with happy emotions were shown, specifically individuals who displayed wiser traits, such as empathy, had speedier responses in the presence of happy stimuli.”

Electroencephalogram (EEG)-based brain recordings showed that the part of the brain called the temporal-parietal junction (TPJ) was activating differently in lonelier versus wiser individuals. TPJ is important for processing theory of mind, or the degree of capacity for empathy and understanding of others.

The study found it more active in the presence of angry emotions for lonelier people and more active in the presence of happy emotions for wiser people.

Researchers also noted greater activity to threatening stimuli for lonelier individuals in the left superior parietal cortex, the brain region important for allocating attention, while wisdom was significantly related to enhanced happy emotion-driven activity in the left insula of the brain, responsible for social characteristics like empathy.

“This study shows that the inverse relationship between loneliness and wisdom that we found in our previous clinical studies is at least partly embedded in neurobiology and is not merely a result of subjective biases,” said study author Dilip V. Jeste, MD, senior associate dean for the Center of Healthy Aging and Distinguished Professor of Psychiatry and Neurosciences at UC San Diego School of Medicine.

“These findings are relevant to the mental and physical health of individuals because they give us an objective neurobiological handle on how lonelier or wiser people process information,” said Mishra.

“Having biological markers that we can measure in the brain can help us develop effective treatments. Perhaps we can help answer the question, ‘Can you make a person wiser or less lonely?’ The answer could help mitigate the risk of loneliness.”

The authors say next steps include a longitudinal study and an intervention study.

“Ultimately, we think these evidence-based cognitive brain markers are the key to developing better health care for the future that may address the loneliness epidemic,” said Mishra.

Loneliness is the feeling that one’s preferred social relations fall short of their actual social relations [1]. In the last decade, loneliness has become a growing area of concern, and with emerging trends suggesting Americans are less socially connected than before, researchers posit loneliness will only become more of an issue over time [2]. In fact, the former 19th US Surgeon General recently argued loneliness is a public health concern [3], labeling problems with loneliness an epidemic [4].

In industrialized countries, researchers estimate that approximately one-third of the population struggle with loneliness, and one-quarter of those will struggle with severe levels of loneliness [5]. In addition, the number of people coping with loneliness may be higher in some regions than in others.

For example, although nationally representative surveys of adults 45 years or older living in the United States indicated that about 35% of people are lonely [6], a study of community-dwelling adults in California found that 76% of their sample reported at least moderate levels of loneliness [7].

The reasons for such variability are unclear; however, loneliness appears to be contagious, occurring in clusters and then spreading through social networks [8], which may explain why loneliness may be unusually high in some geographical areas.

However, loneliness is of particular concern because it can then lead to a number of other psychological and physical problems [9]. For example, daily reports of loneliness predict daytime dysfunction [10], and higher levels of chronic loneliness also predict functional limitations [11], increased systolic blood pressure [12], and greater mortality risk [11,13].

Research with cancer survivors suggests loneliness increases the risk for immune dysregulation, leading to higher levels of pain, fatigue, and depression in female breast cancer survivors [14]. Although a lot of research has focused on the bidirectional relationship between loneliness and depression [11,15], loneliness has also been tied to a higher risk of developing severe common mental disorders, including mood disorders, anxiety disorders, and substance use disorders [16], and to elevated risk of developing Alzheimer disease and other forms of dementia, even when controlling for other risk factors [17,18]. In turn, loneliness predicts increased physician visits among older adults [19] and is associated with higher health care costs [20].

Loneliness During COVID-19

In light of the global coronavirus pandemic, loneliness has become even more of a public health concern. Although the social distancing measures implemented in many countries appear to be effective in slowing the spread of COVID-19, the disease resulting from SARS-CoV-2 [21], researchers have expressed concern that social distancing may result in increased loneliness [22].

Some preliminary research supports these concerns; studies have shown that older adults [23] as well as younger adults (between 18 and 35 years of age) [24] reported elevated levels of loneliness after social distancing measures were implemented. Importantly, although researchers were concerned about the impact of the pandemic on older adults, research suggests that older adults may be more resilient to the negative effects on mental health [25], and younger adults are actually at greater risk for heightened loneliness during the pandemic [26,27].

These heightened levels of loneliness also then place people at greater risk of developing depression or anxiety. In fact, research during the pandemic suggests loneliness may be the strongest predictor of depression and anxiety, even more so than exposure to COVID-19–related situations (eg, self-isolation or knowing someone who had to self-isolate due to COVID-19) and the presence of underlying chronic conditions [26].

Reducing Loneliness

Given the public health implications of chronic and widespread loneliness, there has been increased interest in developing loneliness interventions and even more so during the COVID-19 pandemic [28,29]. However, there is surprisingly little research on loneliness interventions [28]. This could be due, in part, to the fact that historically many clinicians treated loneliness as a component of depression [30]. Although research supports these are related but distinct constructs [29], interventions focusing specifically on loneliness remain limited.

Existing loneliness interventions tend to focus on increasing the individual’s opportunities for social contact, enhancing social support, developing social skills, or addressing maladaptive thinking [29,31]. There is evidence that these interventions have a small, but significant, effect on loneliness [31].

Interventions including social cognitive training such as cognitive behavioral therapy appear to be more effective than other types of interventions [31], which suggests loneliness may have more to do with maladaptive thinking than a deficit in social connection per se [29]. Nevertheless, most loneliness interventions continue to be based on an intuitive assumption that loneliness can be treated by improving social connection [29] and, consequently, focus primarily on increasing opportunities for social interaction [32].

In recent years, there has been a push to offer more psychological and behavioral interventions digitally [33]. Digital interventions tend to be more scalable than face-to-face interventions and reduce many of the structural barriers that prevent people from seeking treatment [34-36].

The need for digital interventions has become even more apparent during the global COVID-19 pandemic [37], when many mental health professionals have had to pivot to teletherapy [38], and mental health concerns are expected to become even more prevalent [39].

Although a number of digital mental health interventions have been developed [33,40-42], digital loneliness interventions are in their infancy, and most of the studies testing these interventions are small pilot or feasibility studies published in the past 1-2 years [43-46]. Moreover, some of these interventions have been tested with a sample of participants with another comorbid condition such as social anxiety disorder [46] or psychotic disorder [47]. There is, however, some preliminary evidence that internet-based interventions can be effective at reducing loneliness [43,48].

Understanding the Experience of Loneliness

To date, most loneliness research has been quantitative in nature, exploring the prevalence, correlates, and consequences of loneliness or testing the effectiveness of loneliness interventions. There are comparatively few qualitative studies on the topic of loneliness, particularly studies exploring lonely people’s reactions to loneliness interventions. Given the complex and subjective nature of loneliness [29,49], better understanding people’s experiences with loneliness and with loneliness interventions may be key to developing effective loneliness interventions.

Qualitative insights may permit identifying themes in the etiology or source of loneliness and the way they engage with loneliness interventions or why such interventions may not be effective. For example, in one qualitative study of older adults who reported feeling lonely, older adults were more likely to view their loneliness as a complex and private matter, rather than an illness, and thus were unlikely to seek help [50].

However, loneliness appears to have different causes and consequences in early and middle adulthood compared to late adulthood [51], and thus, similar insights from a younger population of adults would be valuable.


More information: Cerebral Cortex (2021). … rcor/bhab012/6158980


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