COVID-19 and Human Touch, Two Sides of the Same Coin: An Opinion Article about Touch Deprivation and Future Directions

Abstract

Background. The COVID-19 pandemic introduced unprecedented social distancing measures, resulting in significant deprivation of physical contact. Objective. This opinion article explores the implications of this tactile deprivation on psychological well-being, emphasizing its impact on emotional and cognitive development. Physical contact, particularly social touch mediated by C-tactile fibers, is essential for emotional stability and social bonding. Methods. Drawing on evidence from studies on orphaned children and primates, this opinion article argues for the critical importance of reintroducing physical contact to support mental health. Results. The pandemic’s reduction in physical touch has been associated with increased anxiety, depression, and stress, with notable declines in mood and heightened loneliness. Conclusions. While alternative methods such as virtual reality offer temporary solutions, the article stresses the need for safe, physical interactions as restrictions ease. Future discourse should focus on the long-term effects of touch deprivation and explore effective strategies for mitigating its impacts in similar scenarios.

1. Introduction

Touch is a fundamental aspect of human life, shaping our emotional, psychological, and social well-being. The discovery of C-tactile (CT) fibers, a unique type of unmyelinated low-threshold mechanoreceptive afferents, has provided insight into the biological basis of social touch. These fibers, first identified in mammals by Zotterman in 1939, were not confirmed in humans until 1988 [1,2,3]. CT fibers are particularly responsive to gentle, caress-like touches, typically at speeds between 1–10 cm/s [4] and are encoded by a distinct neural network involving the insular cortex [5,6].

This type of touch, often referred to as “social touch”, has proven to be crucial for maintaining social bonds and emotional regulation. The so-called CT-affective touch hypothesis highlights the unique role of these fibers in fostering emotional connections, promoting relaxation, and enhancing well-being [7]. From infancy, touch is the first sensory system to develop, playing a critical role in early attachment and emotional growth [8,9]. Premature infants, for example, have shown significant improvements in weight gain and overall health when given gentle, nurturing touch [10,11].

The importance of touch extends beyond infancy. Studies involving individuals with sensory neuronopathy, where Aβ afferents are impaired but C fibers remain intact, demonstrate the unique role that CT fibers play in sensory and emotional processing [12,13,14]. Furthermore, research on individuals with genetic conditions affecting nerve growth factor has revealed the essential role of CT fibers in social interactions [15].

The classic experiments by Harlow and Zimmerman [16,17] involving infant macaques further emphasized the importance of touch for emotional security, showing that touch-deprived monkeys preferred comfort over nourishment. Similarly, children raised in environments with limited physical contact, such as orphanages, suffer from emotional and developmental deficits [18]. These findings suggest that touch is not merely a physical experience, but a profound social and emotional necessity, influencing everything from heart rate to stress hormone levels and oxytocin production.

Given this vast body of research, touch deprivation during the COVID-19 pandemic has had far-reaching consequences. As governments enforced stringent social distancing measures to reduce virus transmission and protect overwhelmed healthcare systems, millions were deprived of this essential human interaction. The long-term psychological and physical consequences of this deprivation are becoming increasingly evident, particularly for vulnerable populations such as children and the elderly.

While much research has already explored the effects of social touch e.g., [7,8,9], the COVID-19 pandemic created a unique and widespread context for touch deprivation that has yet to be fully understood. It is therefore essential to examine the existing literature to better comprehend the impact of this global event on mental health and to propose new avenues for therapeutic interventions (see Table 1 for the studies considered and summarized in this article).

2. Discussion

2.1. The Psychological Impact of Touch Deprivation

Researchers have examined both the frequency of positive physical contact among individuals and the role of physical activity in counteracting the effects of touch deprivation. Bruno and colleagues [19] highlighted that social distance could have dramatic consequences on mental health. They estimated the decrease in frequency of positive touch—i.e., hugs, caresses, holding hands, and kisses with both cohabiting and non-cohabiting people—to investigate the consequences of such reduction in psychological distress, e.g., anxiety, and stress. They found that, compared to before the pandemic, there was a significant and general reduction in the frequency of positive touch with cohabiting and non-cohabiting people. This could be explained by the fact that since persons, regardless of whether they were living or not with partners, children, relatives, and friends, reported a statistically significant reduction in physical touch during the pandemic compared to the previous month [19].

The authors also reported that the frequency of hugs with cohabiting partners significantly decreased the symptoms of depression, an effect that the authors linked to increased oxytocin [19].

Interestingly, the frequency of caresses with cohabiting individuals and the frequency of hugs and kisses with non-cohabiting relatives predicted the anxiety symptoms [19].

A crucial point to be considered in interpreting these results is that having positive physical contact could increase the fear of being infected with the virus. Nevertheless, other studies are needed to understand if the reduction is correlated with the fear of infection [19].

In line with these findings, Field and colleagues reported that the frequency of touch with partners was related to lower levels of depressive symptoms during the U.S. COVID-19 lockdown [20] and that physical exercises could reduce the problems associated with touch deprivation in the investigated COVID-19 lockdown sample [21].

Similarly, for clinical staff, exercise during the COVID-19 pandemic in China was thought to reduce psychological and sleep problems [22].

Indeed, the effects of exercise are like those of touch and are linked to a decrease in stress hormones, anxiety, and depression [23] as well as an increase in theta waves that seem to be associated with relaxation and vagal activity, which slows heart rate and decreases blood pressure [24].

The effects of the COVID-19 pandemic have also been investigated in relation to quality of life [25,26,27,28].

In contrast to some studies that were conducted in a single country [25,26,27], Hasenack and colleagues [28] reported potential associations in people from different countries. They investigated the potential association between COVID-19 regulations, longing for touch [i.e., the discrepancy between touch frequency and the desire for touch, referred to as social consensual touch], and Quality of Life in people from different countries [28]. In this study, 83% of participants expressed a desire for physical touch, which was linked to reduced physical, psychological, and social well-being [28].

Despite these results suggesting that the COVID-19 regulations have had negative consequences on the well-being of the general population due to increased longing for touch and consequently negative impact on physical and psychological well-being, longing for touch has also been reported in non-pandemic situations [29]. This point must be considered in the interpretation of these results.

2.2. Intimate Touch, Anxiety, and Loneliness

One specific kind of touch has also been investigated, i.e., intimate touch. Intimate touch seems to be the most craved, and the desire for intimate touch became stronger, as the social distance time increased [30]. Interestingly, while the deprivation from intimate touch was associated with anxiety and loneliness, the degree of desire seemed to depend on individual differences in attachment. In particular, individuals who are more anxiously attached craved more touch.

It has also been reported that there is a correlation between the lack of intimate touch and self-reported anxiety and loneliness, i.e., the greater the lack of touch, the worse the self-report. Importantly, the lack of touch considers touch experienced before COVID-19. Nevertheless, the lack of intimate touch on loneliness overcomes the effects of touch on anxiety [30].

2.3. Touch Deprivation and Perception of Pleasantness

Interestingly, Meijer and colleagues [31] explored the relationship between longing for touch and the perception of the pleasantness of touch. They reported that the perceived pleasantness of the CT-optimal touch video significantly increased as the level of longing for touch and age increased. CT-optimal touch is considered touch that modulates the CT fibers and is encoded as a pleasant social-related touch. People in complete lockdown perceived the CT-optimal touch video to be significantly more pleasant than those under social distancing measures and those in lockdown. However, the perceived pleasantness was not associated with the duration of regulations or gender. Importantly, concerning the CT non-optimal touch video, the pleasantness scores were positively associated with levels of longing for touch, and participants in complete lockdown perceived the video as being more pleasant than people in lockdown or under socially distancing measures [31].

2.4. Study Limitations: Pandemic or Pre-Pandemic Deprivation?

One significant limitation in understanding the full impact of touch deprivation during the COVID-19 pandemic is the lack of pre-pandemic comparisons. Even in societies without social restrictions, a substantial percentage of healthy individuals report experiencing a longing for touch [29]. Before the pandemic, research on touch deprivation was largely confined to specific cases such as children raised in orphanages. This narrow focus leaves a gap in our understanding of how widespread and impactful the longing for touch truly is.

It would be particularly insightful to compare pre- and post-pandemic conditions to assess whether the COVID-19 crisis exacerbated an already existing desire for physical contact. A more detailed examination of how the pandemic influenced this longing, as suggested by Meijer et al. [31], could provide valuable insights into the evolving nature of human social needs in response to prolonged isolation.

Despite it being impossible to compare the results during the pandemic with those before, it could be interesting to compare the results during the pandemic with those after the pandemic. Considering that four years have passed since the pandemic, it could be interesting to make such a comparison over time. The analysis could help us understand if the consequences of touch deprivation are still present, or if they are decreasing. Moreover, other studies are needed to understand the perception of CT-touch pleasantness to better shed light on the relationship between touch longing, touch deprivation, and the COVID pandemic.

2.5. Study Limitations: Cultural Context

The cultural context is crucial when interpreting results related to touch deprivation. For example, most participants in the Meijer et al. study [31] were from Italy, a high-contact culture. The authors speculate that stricter COVID-19 regulations combined with a cultural norm of frequent physical contact likely resulted in higher perceived pleasantness of touch. Comparing these findings with those from low-contact cultures could offer important insights into how cultural norms influence the experience of touch deprivation. Additionally, examining individuals from various cultural backgrounds may help us understand the different effects of touch longing, and deprivation.

2.6. Future Directions

While we reflect on the impacts of touch deprivation, it is crucial to also explore solutions. Alternative therapies such as physical exercise, virtual reality, and yoga could mitigate some of the negative effects associated with the absence of touch [24,32]. Such approaches could provide practical guidelines for managing future pandemics or periods of social distancing where physical touch may be restricted.

Additionally, emerging technologies such as artificial intelligence and social robots hold the potential to offer new forms of interaction and companionship, providing comfort and reducing feelings of isolation during periods of social distancing [33,34].

Future research should focus on the long-term effects of touch deprivation, particularly in vulnerable populations. Studies comparing high-contact cultures, like Italy, with low-contact cultures could yield insights into how cultural norms influence the craving and perception of touch [31]. Additionally, research into the use of alternative forms of contact, such as virtual touch or mindfulness techniques, could provide valuable interventions for maintaining well-being during future crises.

Do the effects of longing for touch continue post-pandemic? Hasenack and colleagues [35] reported that more than three-quarters of people still experience less social touch than they desired post-COVID-19. However, when considering the implications and making future predictions regarding the effects of touch deprivation, it is essential to acknowledge the limitations of the cited studies. Many of these investigations were conducted under specific conditions, such as during lockdowns, and may not account for gender imbalance in their studies, individual differences in cultural practices, pre-existing psychological conditions, or varying levels of access to physical touch. Additionally, some studies relied on self-reported data, which can introduce biases or inaccuracies. Therefore, any future research or interventions should consider these limitations to provide a more comprehensive understanding of the long-term impact of touch deprivation and to develop more targeted strategies for mitigating its effects.

Table 1. Summary of the reported studies.

Investigated Aspect/s	Results	Refs.
Frequency of positive contact with cohabiting and non-cohabiting	Reduction with cohabiting and non-cohabiting people The frequency of hugs with the cohabiting partner significantly decreased the symptoms of depression (increment of oxytocin) The frequency of caresses with cohabiting and the frequency of hugs and kisses with non-cohabiting relatives predicted the anxiety symptoms	[19]
	The frequency of touch with partners was related to lower levels of depressive symptoms	[20]
Physical exercised as a solution	Physical exercise could reduce the problems associated with touch deprivation	[21]
	Exercise for clinical staff reduce psychological and sleep problems	[22]
Quality of life	Reduction of physical, psychological, and social well-being	[25,26,27,28]
Intimate touch	The deprivation of intimate touch was associated with anxiety and loneliness The degree of desire depends on individual differences in the attachment Correlation between the lack of intimate touch and self-reported anxiety and loneliness	[30]
Perception of the pleasantness of touch	People in complete lockdown perceived the CT-optimal touch video to be significantly more pleasant than those under social distancing measures and those in lockdown Participants in complete lockdown perceived the CT non-optimal touch video tovbe more pleasant than people in lockdown and under socially distancing measures	[31]

Table 1. Summary of the reported studies.

Investigated Aspect/s	Results	Refs.
Frequency of positive contact with cohabiting and non-cohabiting	Reduction with cohabiting and non-cohabiting people The frequency of hugs with the cohabiting partner significantly decreased the symptoms of depression (increment of oxytocin) The frequency of caresses with cohabiting and the frequency of hugs and kisses with non-cohabiting relatives predicted the anxiety symptoms	[19]
	The frequency of touch with partners was related to lower levels of depressive symptoms	[20]
Physical exercised as a solution	Physical exercise could reduce the problems associated with touch deprivation	[21]
	Exercise for clinical staff reduce psychological and sleep problems	[22]
Quality of life	Reduction of physical, psychological, and social well-being	[25,26,27,28]
Intimate touch	The deprivation of intimate touch was associated with anxiety and loneliness The degree of desire depends on individual differences in the attachment Correlation between the lack of intimate touch and self-reported anxiety and loneliness	[30]
Perception of the pleasantness of touch	People in complete lockdown perceived the CT-optimal touch video to be significantly more pleasant than those under social distancing measures and those in lockdown Participants in complete lockdown perceived the CT non-optimal touch video tovbe more pleasant than people in lockdown and under socially distancing measures	[31]

3. Conclusions

COVID-19 has taught us that human well-being cannot be measured solely by physical health metrics. Touch is an emotional and social necessity, and its absence has left deep scars on our collective psyche. As we rebuild our lives post-pandemic, we must prioritize reintroducing physical touch, recognizing its value in mental and emotional health. By doing so, we can prevent future mental health crises and promote a more balanced approach to public health interventions.

However, further studies are necessary to evaluate the effects, not only in healthy adults but also in children and individuals with physical and psychological conditions. These studies will greatly contribute to the exploration of new solutions for similar situations in the future as well as in the present, where people are living in comparable conditions of deprivation. The goal is to prevent the deterioration of critical conditions or the emergence of critical psychological situations.