Eating behavior and alcohol use

10Some of the negative effects of loneliness on health may be explained by lonely individuals being more likely to engage in health-compromising behaviors, such as excess alcohol consumption or overeating (Hawkley/Cacioppo 2010). With the majority of the population requested to observe social distancing, self-isolation or quarantine, changes in lifestyle and health behaviors seem inevitable.

11Of the substances most likely to be abused, alcohol is by far the most common in large parts of the world (Manthey et al. 2019). There is evidence that social or interpersonal isolation is one of several factors contributing to excessive alcohol consumption (Fairbairn/Sayette 2014). This has been confirmed by recent findings on COVID-19 confinement measures, which show an increase in the purchased volumes of alcohol in many countries during the lockdown (Arora/Grey 2020). For example, in Australia, spending at liquor stores in the week to March 27 was up 86 % compared with the same time last year, and important post-pandemic onset rises in spending on alcohol have also been reported in the United Kingdom and the United States (ibid). Studies investigating the impact of social isolation on substance use indicate a greater propensity of socially isolated individuals to abuse alcohol (Åkerlind/Hörnquist 1992) or be diagnosed with substance use disorder (Chou/Liang/Sareen 2011). This is of particular concern, given the short- and long-term consequences of excessive alcohol consumption (Arora/Grey 2020). In the short term, heavy drinking affects the adaptive immune system (Pasala/Barr/Messaoudi 2015), with particular effects on the capacity of the lungs to fight off infectious diseases like COVID-19. Furthermore, alcohol abuse has been found to be related to violent behaviors in a number of studies (Boden/Fergusson/Horwood 2012; Bushman/Cooper 1990), including domestic violence (Wilson/Graham/Taft 2014).

12Eating is one of the most fundamental human behaviors pertaining to health. In response to the COVID-19 pandemic and associated confinement measures, several studies have already been carried out to explore the effects on dietary behaviors and eating disorder symptoms. Changes in eating behavior are common under stressful conditions (Adam/Epel 2007; Vögele/Lutz/Gibson 2018), and COVID-19 related social distancing measures have been found to be associated with overeating and the consumption of food of poorer quality (Papandreou et al. 2020). In a recent study, participants reported increased consumption of unhealthy food, loss of control over eating and more snacking between meals during confinement compared to before the lockdown (Ammar et al. 2020). The COVID-19 pandemic and the related confinement measures seem to exacerbate the risk for overeating and weight gain, particularly among vulnerable individuals such as children and patients with an eating disorder (Fernández‐Aranda et al. 2020). Weight gain and obesity, however, are not the only consequences of a poor diet and a positive energy balance. Unhealthy dietary habits also promote the onset and exacerbation of multiple chronic diseases, including coronary heart disease, type 2 diabetes mellitus, hyperlipidemia, and stroke (Arora/Grey 2020). Consequently, short- and long-term consequences of these alterations to dietary patterns during social isolation need to be examined to prepare for future pandemics.

13Stay-at home instructions and social distancing rules may exacerbate disordered eating behaviors or alcohol consumption through multiple pathways, and particularly in vulnerable individuals. First, the time available to engage in harmful health or addictive behaviors has increased (Håkansson et al. 2020). With many public events being cancelled throughout the lockdown periods, schools, universities and many workplaces being closed, and people encouraged to stay at home, many people have more free time and/or may be more easily tempted by foods or alcoholic beverages while staying at home (Fernández‐ Arandaet al. 2020). Second, boredom as a result of quarantine can be considered a risk factor for eating more and to consume food of a poorer quality compared to non-confined living conditions (Ammar et al. 2020).

14In addition, social isolation and loneliness can lead to emotional distress, for which alcohol and food may be used to cope with it. In animal models the abrupt reduction of social interactions enhances stress followed by increased food intake (Schipper et al. 2018) and substance use (Cheeta/Irvine/File 2001; Thielen et al. 1993). Human studies on this topic are limited, as situations of sudden reductions in social connections at the population level are relatively uncommon. Nevertheless, stressful life events in general are risk factors for the development and maintenance of eating disorders, and predict relapse (Degortes et al. 2014; Grilo et al. 2012; Pike et al. 2006). In a similar vein, stressful life events are associated with increased alcohol consumption and may initiate or maintain alcohol use disorders (Keyes/Hatzenbuehler/Hasin 2011).

15In addition to these effects, some people might – as a result of confinement measures - have had limited access to food and alcoholic beverages due to financial constraints, panic buying and stockpiling, the temporary closure of some food suppliers and bars or pubs, or limited time to shop for groceries. Initial findings suggest that the number of individuals who are food insecure has risen exponentially during the first weeks of the pandemic (Loopstra 2020). Previous research suggests that food insecurity and associated fluctuating household food supplies contribute to a “feast or famine” eating pattern, characterized by alternating periods of food abundance and overconsumption, followed by food scarcity and dietary restraint (Bove/Olson 2006; Cooper et al. 2020). Regarding alcohol accessibility, two mutually exclusive mechanisms may apply (Rehm et al. 2020). One mechanism suggests that the closure of bars, pubs, hotels and restaurants in many countries, associated with increased psychological distress during the crisis, might lead to an increase in home drinking and associated health and social harms, not only for the drinker but also for other household members (Reynolds/Wilkinson 2020). Accordingly, previous studies found links between off-premise consumption of alcohol and traumatic injury (Livingston 2011), domestic violence (Curtis et al. 2019), and intimate partner violence (Laslett et al. 2015). Another set of mechanisms predicts reductions in alcohol consumption due to lower availability and restricted financial means. Rehm and colleagues (2020) suggest that the timing of these effects should also be considered, as some effects might be immediate (i.e., during the crisis) while others may apply in the longer term (i.e., after the crisis).

16Finally, eating patterns and alcohol use might also be influenced by restricted healthcare access during the COVID-19 pandemic. Especially vulnerable individuals with pre-existing mental health problems might experience increased symptoms or have their treatment disrupted (Duan/Zhu 2020; Fernández‐Aranda et al. 2020; Xiang et al. 2020). Individuals with a diagnosed eating or substance use disorders are usually monitored by health care providers and need regular consultations and targeted interventions. The onset of the COVID-19 crisis, however, has resulted in a depletion of healthcare resources, and hospitals were forced to increase their capacity for COVID-19 patients, often at the expense of non-COVID-19 patients, including those with mental disorders. Furthermore, physical distancing restrictions and the risk of contracting COVID-19 from being physically present in a medical setting may be a reason for individuals with mental health problems to avoid mental health facilities. Although there has been a rapid implementation of online- and eHealth measures in many countries, some aspects of remote treatment can be challenging to monitor without direct face-to-face contact (Fernández‐Aranda et al. 2020), especially in more extreme cases (e.g., severely underweight, self-injury).

17In summary, the COVID‐19 crisis has created a situation across the globe likely to increase the risk for social isolation and loneliness through the implementation of social distancing measures. While considered necessary at this time to contain the spread of the virus, these measures may increase the risk for developing disordered eating patterns and problematic alcohol use through multiple pathways, while also contributing to the decrease of protective factors and elevating barriers to health care.

Social isolation as a risk factor for depression and anxiety

18The COVID-19 pandemic is associated with a variety of stressors, such as worries about being infected or infecting others, constraints in daily life, or limited social contacts. A large body of literature has demonstrated the links between social isolation and depressive (Santini et al. 2015) and anxiety symptoms (Teo/Lerrigo/Rogers 2013). Symptoms of anxiety may include constant worrying and avoidance of feared situations, while depressive symptoms include e.g. depressed mood and loss of interest in activities. People are likely to be affected to different degrees, from none or mild symptoms to a full-blown anxiety or depressive disorder. In the current Diagnostic and Statistical Manual of Mental Disorders (DSM-5), depressive disorders encompass, among others, the mostly episodic major depressive disorder, and persistent depressive disorder, which lasts for at least two years (American Psychiatric Association 2013). The category anxiety disorders lists, among others, generalised anxiety disorder, specific phobia, panic disorder, and agoraphobia. Based on these diagnostic categories, it has been reported that, over a 12-month period, around 12 % of the European population suffer from anxiety disorders and around 8 % from mood disorders (i.e. depressive and bipolar disorders) (Wittchen/Jacobi 2005). These numbers refer to diagnosed disorders. Subclinical symptoms of depression and anxiety are likely to be even more common and may have a significant impact on quality of life.

19In the extant research on the COVID-19 outbreak, depressive and anxiety symptoms were primarily assessed with questionnaires. As opposed to a clinical interview, questionnaires do not provide a mental disorder diagnosis, but rather a measure of symptom severity. A cut-off score determines at which point symptoms are so severe that they are likely to be clinically relevant. Using this procedure, previous studies with German representative samples have shown prevalence rates of clinically relevant depressive symptoms of 5.6 % (Kocalevent/Hinz/Brähler 2013), and 6.0 % for anxiety symptoms (Löwe et al. 2008). A study conducted in Germany during the pandemic showed prevalence rates of 14.3 % and 16.6 % for depressive and anxiety symptoms, respectively (Bäuerle et al. 2020), suggesting that the burden of mental disorders has increased substantially during the pandemic. Relatively high levels of depressive and anxiety symptoms during the pandemic have been reported in other countries as well, for example the U.S. (Liu et al. 2020), and China (Huang/Zhao 2020). A recent meta-analysis reported prevalence rates of 31.9 % for anxiety and 33.7 % for depression during the COVID-19 pandemic (Salari et al. 2020). Although it is likely that the prevalence of current mental disorders is lower, this implies that approximately one third of the population was affected by significant symptoms of anxiety or depression. It should be noted, however, that these meta-analytical results were based on only 5 studies with a total sample size of 9074 respondents. While this is understandable considering the short period of time since the outbreak of COVID-19, it also highlights the preliminary status of these results.

20Most extant studies only collected data, when lockdown measures were already in place. The question remains, therefore, whether symptoms of depression and anxiety were more prevalent during the pandemic than before. A study conducted in the U.S. (Ettman et al. 2020) compared levels of depressive symptoms during the pandemic to levels reported by comparable, national representative samples two to three years before the pandemic. As the result show, depressive symptoms had increased more than 3-fold during the pandemic. The same study may help to answer another question: are more people becoming depressed or are those who were already depressed becoming more severely depressed? According to their depressive-symptom scores, participants were divided into five groups: none, mild, moderate, moderately severe, or severe symptoms. Results showed that during the pandemic, the percentage of people with no symptoms was 27.7 % lower than before. This means that the number of people experiencing at least some depressive symptoms increased by almost 30 % during the pandemic, i.e. more people became depressed. At the same time, the highest increase was seen in the category of severe depressive symptoms, which showed a 7.5-fold increase compared to pre-pandemic levels. It seems likely, therefore, that pre-existing depressive symptoms aggravated during the pandemic. In conclusion, the study by Ettman et al. (2020) shows that the pandemic led to both a higher number of those reporting depressive symptoms, and an increase in the severity of depressive symptoms.

21The experience of loneliness was particularly associated with depression and anxiety symptoms during the COVID-19 outbreak (Palgi et al. 2020), but also with suicidal ideation (Killgore et al. 2020). On a more positive note, social support was associated with lower levels of depression symptoms (Tull et al. 2020), especially family support (Liu et al. 2020). A study with Canadian adolescents showed particularly interesting results regarding different types of social support. Family time had positive effects, but social media use had negative effects on depressive symptoms (Ellis/Dumas/Forbes 2020). Elderly people were especially affected by personal losses (van Tilburg et al. 2020). These results underline interindividual differences in how people experience the pandemic and its consequences. They also show, however, that social support is important to counteract feelings of loneliness induced by social distancing measures. Loneliness has negative and social support positive consequences for mental health.

22In summary, the COVID-19 pandemic has had detrimental effects on mental health, with a significant increase in depressive and anxiety symptoms. Social support is important for buffering the negative effects of social distancing measures on mental health, but social media use may have counterproductive effects.

Experimental ostracism paradigms

25To investigate the short-term effects of ostracism, several social exclusion paradigms and manipulations have been developed and used in laboratory research. Paradigms differ in terms of whether participants interact with other individuals or with computer avatars, or whether written material manipulations have been used to induce feelings of social exclusion.

26Get Acquainted (Nezlek et al. 1997). This paradigm involves a get-acquainted discussion within a group consisting of the actual participant and a number of confederates. The experimenter gives examples of topics to be discussed in the group (e.g., favorite movies, major in college). The group is then separated and each person is asked to identify the person from the group they would most like to work with. Participants assigned to the inclusion condition learn that everyone wanted to work with them, while participants assigned to the exclusion condition learn that nobody wanted to work with them.

27Ball tossing paradigm (Williams 1997). This paradigm involves a ball tossing game that appears to have no connection with the experiment itself. The participants (one actual participant and two confederates) are requested to wait in a room for the return of the experimenter. One of the two confederates notices a ball and starts throwing it around. In the inclusion condition, the actual participant continues to receive the ball for about one-third of the time. In the exclusion condition, however, the participant is excluded by never receiving the ball again while the confederates continue to play with enthusiasm.

28Cyberball (Williams et al. 2000; Williams/Jarvis 2006). The Cyberball paradigm is a virtual analogue to the ball-tossing game. Participants are requested to play a game of virtual ball toss as a means to exercise their mental visualization skills. They are told that their actual ball tossing performance is unimportant, but that they should mentally visualize the entire experience. Participants randomly assigned to the inclusion condition, receive the ball in about one-third of the time. In the exclusion condition participants are excluded by the virtual players and do not receive the ball.

29Life-alone prognosis paradigm (Twenge et al. 2001). The life-alone prognosis paradigm consists of a personality test designed to provide the participant with false feedback that he/she will either live a life filled with meaningful relationships, a life alone, or a life of misfortune. Participants randomly assigned to the future belonging condition are told to imagine that they would have rewarding and long-lasting relationships, while those assigned to the future alone condition are asked to envisage that they would end up alone later in life and that current friendships would not last. Participants in the misfortune control condition are requested to visualize mentally that they would be at risk of accidents, and would be involved in many accidents.

Short-term effects on fundamental needs

30Human fundamental needs include belonging (need to belong to a group and to have pleasant interactions with others), control (need to perceive control over one’s social environment), meaningful existence (need to feel recognized and being worthy of attention), and self-esteem (need to maintain a reasonably high self-esteem) (Williams 2009). To investigate the short-term effects of ostracism on these basic needs in the laboratory, Zadro and colleagues (2004) developed the “Needs-threat questionnaire”, a self-report measure to assess the degree to which the four needs of belonging, control, meaningful existence and self-esteem are satisfied. Following a social exclusion paradigm (e.g., Cyberball), participants are asked whether they felt included or excluded during the experiment and to what extent their needs were unfulfilled. Using this scale, there is convincing evidence that ostracism lowers self-reported levels of belonging, control, meaningfulness and self-esteem in individuals (Eisenberger et al. 2003; Seidl et al. 2020; Williams et al. 2000; Zadro et al. 2004).

31Although we all perceive a threat to our fundamental needs if subjected to ostracism, some individuals are more affected by its effects than others. A recent study conducted by Seidl and colleagues (2020) demonstrated that individuals diagnosed with an affective disorder (e.g., depression, borderline personality disorder) reported overall lower values on the “Needs-Threat questionnaire” following the Cyberball game compared to healthy controls, indicating that their needs were more threatened by being ignored and excluded. Zadro and colleagues (2006) investigated the persistence of the short-term effects of ostracism in high and low socially anxious participants. In their study, participants completed the “Needs-Threat questionnaire” once after the game and 45 minutes later. The results indicated that being ostracized affected both groups in the first place, but high socially anxious individuals showed a slower recovery compared to low socially anxious participants (Zadro et al. 2006).

32Taken together, the empirical evidence suggests that perceived social exclusion threatens psychological needs, including belonging, control, meaningful existence, and self-esteem. Furthermore, it has been demonstrated that the short-term effects of ostracism are more pronounced and persistent among vulnerable participants.

Short-term effects on mood

33It seems obvious that the experience of being ostracized, social isolation and loneliness is emotionally painful and evokes unpleasant feelings of distress. Research investigating the short-term effects of ostracism, however, shows mixed results. On the one hand, some studies suggest that ostracism increases self-reported distress such as anxiety, sadness, and anger (e.g., Bernstein et al. 2008 and 2010; Seidl et al. 2020). Williams and colleagues (2000) also identified a distress pattern that was linearly associated with the degree of ostracism to which the participants were exposed. In their study, participants were randomly assigned to one of four conditions that varied in the level of ostracism, i.e. overinclusion, inclusion, partial ostracism and complete ostracism, with a chance to receive the ball 67 %,, 33 %, 20 % and 0 %, respectively. The more the participants were ostracized, the more they reported to feel bad, sad, tense, and rejected. On the other hand, there is evidence that social exclusion leads to feelings of emotional numbness (e.g., Baumeister et al. 2005; DeWall/Baumeister 2006; Twenge et al. 2003). Interindividual differences in the sensitivity to ostracism are likely to determine emotional responses to social exclusion. Future research is warranted to examine underlying mechanisms determining the emotional response to ostracism.

Short-term effects on physiology and brain activity

34In addition to its effects on fundamental needs and mood, acute social rejection results in immediate physiological stress responses, such as elevated heartrate (Iffland et al. 2014; Liddell/Courtney 2018; Williamson et al. 2018), lower skin temperatures (IJzerman et al. 2012), and increased release of the stress hormone cortisol (Beekman et al. 2016; Blackhart et al. 2007). There is also evidence that ostracism activates specific brain areas associated with the perception and processing of physical pain. For example, Eisenberger and colleagues (2003) conducted a neuroimaging study in which social exclusion was induced by the Cyberball paradigm. While playing the game, the participants’ brain activity was assessed using functional magnetic resonance imaging (fMRI). After playing the game, participants were asked to fill out questionnaires assessing how excluded and socially distressed they felt during the game. The results suggest that the dorsal anterior cingulate cortex (dACC) and right ventral pre-frontal cortex, which are known for their role in the processing of physical pain, were more active during the exclusion than inclusion condition. Moreover, an increase in the activity of the dACC was associated with greater self-reported distress. These results were replicated in numerous subsequent studies (Krill 2009; Le et al. 2020; Onoda et al. 2010; Riva et al. 2011) and suggest that the experience of social rejection is processed in a similar way to physical pain.

Implications of short-term effects of loneliness in times of COVID-19

35From a research perspective the COVID-19 pandemic and the associated social distancing measures represent a unique community-wide paradigm inducing feelings of social isolation. It is reasonable to assume that people experience the current crisis as a daily threat to their fundamental needs, which worsens their mood and triggers physical stress responses and social pain. In the long-term, this could lead to significant deterioration in their general state of health. Recent studies have shown that people with pre-existing mental and physical health problems are particularly affected and reported higher levels of depression and anxiety in response to COVID-19 social distancing measures (e.g., Alonzi et al. 2020). Nevertheless, there is a need to not only identify vulnerable subgroups, but also to investigate protective factors against the negative effects of COVID-19 confinement measures on mental and physical health.

Interoception and social isolation

40Interoception refers to the perception of signals from inside the body, such as heartbeats, filling status of the stomach or the urinary bladder (Khalsa et al. 2018). It plays an important role in the experience and regulation of emotions, and could, therefore, posit a crucial mechanism mediating between social isolation on the one hand and loneliness and mental distress on the other.

41One way to assess interoception is by using self-report questionnaires. Typical questions cover the frequency one is aware of a specific bodily sensation (e.g., palpitations, breathlessness, gastric contractions etc.) and reflect, therefore, the subjective tendency to focus on physical symptoms. Another approach to assess interoception is the comparison of an actual bodily event (e.g., occurrence of a heartbeat) and its perception. For example, the number of heartbeats occurring during a certain time period can be compared with the number of perceived heartbeats. There is an established terminology that defines the self-reported tendency to focus on internal bodily signals as ‘interoceptive sensibility’, whereas the correspondence between actual and perceived bodily signals has been labelled ‘interoceptive accuracy’ (Garfinkel et al. 2015).

42Interoception plays an important role for the experience and regulation of emotions. Early studies suggested that two components are essential for the presence of an emotion: a change in body functions that can be perceived (e.g., heart racing or crying) and the attribution of these changes to an event that might have evoked an emotional response. For example, if individuals were told that heart racing was due to side effects of an administered substance, they are less likely to report emotions, such as anger or anxiety, than individuals, who did not receive this information and thus attribute their bodily percepts as an indicator of an emotion (Schachter/Singer 1962). This example shows that not only the change in body functions is relevant, but also its perception. As there is large variability in the precision to perceive body signals (‘interoceptive accuracy’), this also has consequences for the experience of emotions. Individuals with higher interoceptive accuracy report more intense emotional states, such as arousal (Barrett et al. 2004). Furthermore, individuals with higher interoceptive accuracy seem to also have higher scores in empathy, suggesting that the perception of one’s own bodily states helps to recognize and to re-experience the emotions of others (Grynberg/Pollatos 2015). On the one hand, it could be argued that these individuals may be more susceptible for mental disorders that are associated with strong emotions and emotional disturbances, such as depression, anxiety or borderline personality disorder. On the other hand, the capacity to experience intense emotions may be a pre-requisite to effectively down-regulate emotional states. This process, also known as ‘emotion regulation’, involves different strategies, such as the suppression of an emotion or the reappraisal of the eliciting context. Individuals with high interoceptive accuracy are more effective in using reappraisal strategies when confronted with pictures evoking emotional responses (Füstös et al. 2013), or in social situations, in which a fake gambling opponent presents an unfair offer (vanʼt Wout/Faught/Menino 2013). Emotion regulation problems are frequent in mental disorders, so much so, that they are currently discussed as a trans-diagnostic criterion across most mental disorders (Joormann/Stanton 2016). In summary, high precision in perceiving signals from inside the body represents an important pre-requisite to down-regulate (negative) emotions, which is a protective (i.e. resilience) factor against the development of mental disorders.

43Ostracism and social isolation are considered particularly strong emotional challenges. When investigated in the laboratory, being ostracized in group discussions or collaborative video games (e.g., Cyberball) is associated with a decrease in positive and an increase in negative affect, and increased feelings of exclusion and need for affiliation with others. Nevertheless, not all individuals are equally affected: the better individuals are at perceiving their own bodily signals, the less susceptible they are for these negative emotional consequences (Pollatos/Matthias/Keller 2015; Werner et al. 2013). Follow-up studies showed that this effect is due to the more effective use of emotion regulation strategies involving suppression or reappraisal after social exclusion (Pollatos et al. 2015). Interestingly, interoceptive accuracy temporarily decreases after an ostracism paradigm (Durlik/Tsakiris 2015), whereas the brain networks that mediate interoception, are activated by ostracism (Cacioppo et al. 2013; Eisenberger 2012; Eisenberger et al. 2006). Two conclusions can be drawn from these observations. First, when confronted with a major social challenge, such as ostracism, the experience and down-regulation of negative emotions require cognitive, attentional and self-regulatory resources, which reduces the capacity to accurately perceive bodily signals, as both are processed by partially the same brain networks. Second, as being ostracized temporarily reduces interoceptive accuracy, individuals with a poorer baseline interoception are even more affected, leaving them with particularly low interoceptive accuracy during a social challenge and, therefore, fewer resources (e.g., emotion regulation) to effectively cope with the experience of being ostracized.

44Although the mechanisms that affect the development of interoceptive capacity remain largely unknown at this time, first evidence points towards the possibility that the development of interoceptive capacities benefits from social relationships during childhood, such as indicated by a secure attachment style (Oldroyd/Pasupathi/Wainryb 2019). These findings remain preliminary, however, as this relationship is based on self-reports only (interoceptive sensibility), whereas evidence on attachment and interoceptive accuracy is scarce.

45Loneliness, as the personal experience of social isolation, can be construed as the result of permanent ostracism. As previously described, it depends, however, not only on the objective number of social contacts (i.e. social network), but on the mismatch between the perceived and desired level of social connectedness. As this definition implies that a person’s individual characteristics greatly contribute to perceived loneliness, it is important to understand the mechanisms behind the generation of feelings of loneliness. Only an in-depth understanding of these mechanisms may allow identifying potential predictors of loneliness in the future, and possible intervention targets to relieve loneliness. First evidence indicates that emotion recognition and empathy may be deficient in those affected by loneliness (Beadle et al. 2012). It is plausible to assume, therefore, that individuals experiencing high levels of loneliness also show lower interoceptive accuracy. In line with this assumption, it has been proposed that one mechanism underlying loneliness is that concerned individuals focus their attention mainly on stimuli outside of the body (i.e. exteroceptive attentional bias), as they may be particularly vigilant and vulnerable for social threats. This bias may reduce their capacity, accuracy and flexibility in interoception (Arnold/Winkielman/Dobkins 2019). In conclusion, deficient interoception due to a bias towards exteroceptive stimuli indicating social threat may be one factor contributing to the generation of feelings of loneliness.

46From a research perspective the COVID-19 crisis and the associated lockdown measures represent a unique community-wide paradigm imposing social isolation. It could be argued that these social isolation measures temporarily decrease interoceptive accuracy, as previously seen in ostracism experiments in the laboratory. This has the potential to promote loneliness, but again, not everyone will be affected in the same way and to the same degree. Depending on the pre-existing levels of interoceptive abilities, some will end up with a lower level of interoception than others. Given that high interoceptive abilities represent a resilience factor against emotional problems, we would argue that those individuals, who can maintain higher interoceptive accuracy, are less susceptible for depression and anxiety symptoms during the COVID-19 pandemic. A first study investigating the effect of a mindfulness meditation training during the lockdown has shown an increase in self-reported interoceptive sensibility and a decrease in depression (Matiz et al. 2020). Future studies should clarify if interoceptive accuracy is affected in the same way. In summary, interoceptive abilities may represent an important resilience factor against loneliness, depression and anxiety during the COVID-19 crisis.

Emotion regulation as a factor mediating between social isolation and mental health

47In the wake of the COVID-19 pandemic, many changes have been introduced that affect our daily lives. Many of these changes are experienced as stressful by many individuals, with a potential negative impact on mental health (Salari et al. 2020). Yet, individuals differ in the ways they cope with stress and how they regulate associated negative emotions. For example, changing the way one thinks about, or reappraises, a stressful situation is positively associated with mental health, while suppressing one’s emotional expression has a negative impact (Hu et al. 2014). First studies conducted during the COVID-19 outbreak have shown that emotion regulation played an important role in how strongly people experienced loneliness and to what extent their mental health was affected (Gubler et al. 2020). Cognitive reappraisal was shown to buffer the impact of perceived stress on anxiety symptoms in isolated people during the COVID-19 pandemic (Xu et al. 2020). Similarly, engaging in more reappraisal and fewer suppression was associated with fewer symptoms of post-traumatic stress disorder after the COVID-19 outbreak in China (Jiang et al. 2020). Emotion regulation has also been shown to influence adherence to protective measures (Rubaltelli et al. 2020).

48In addition to cognitive emotion regulation strategies, people may engage in certain behaviors to feel better. A recent study investigated the impact of such coping behaviours during the COVID-19 pandemic on depressive and anxiety symptoms (Fullana et al. 2020). The results showed that eating healthily and not following COVID-19 news too closely were positive predictors for mental health. Furthermore, engaging in leisure activities, going outside, and having a routine had positive effects on depressive symptoms. These findings show that the way people deal with negative emotions and other consequences of the pandemic and associated protective measures, is essential in determining mental health outcomes. Future research should, therefore, investigate how people can be supported in developing effective coping strategies, to prevent negative mental health outcomes. In addition, improving emotion regulation may have a positive impact on people’s adherence to protective measures (Rubaltelli et al. 2020). This makes emotion regulation a prime target for interventions with the aim of supporting individuals during this and possible future pandemics.

Life satisfaction

53We asked people how satisfied they were with their life overall during the week preceding the survey. German residents reported the highest level of satisfaction with their life over the past week, followed in decreasing order by Luxembourg, Spain, Sweden, and France. Italy was the country where residents reported the lowest life satisfaction in the last week, and this difference was statistically significant compared to all other countries except for France.

54Across all countries, life satisfaction during the week preceding the survey was lower for the unemployed, those living alone and those in the lowest income group. In contrast, life satisfaction was higher for individuals living with a garden and for those aged 65 years and older. Comparisons between countries showed that the negative effects for those in the lowest income group were particularly large in France and Luxembourg. While there were no negative effects of unemployment on life satisfaction in Luxembourg and Germany, the effect of cohabitation status (i.e. living with a partner/family or living alone) was largest in Luxembourg. The number of children was negatively correlated with life satisfaction only in Luxembourg, perhaps reflecting the higher levels of perceived stress (for example in relation to child care), although it remains unclear why this would only be the case in Luxembourg.

Perceived stress and worries

55Participants from Italy, Spain, and Luxembourg indicated significantly higher levels of stress during the last two weeks than those from France, Germany, and Sweden. Overall, stress levels were similar to normative data from these countries (e.g. France) or slightly higher (e.g. Germany). There are several reasons why people may feel stressed. The questionnaire used to assess stress (PSS‐10) did not specifically refer to stress because of the risk of catching COVID‐19. The question on worries indicated that Luxembourgish residents were very worried about their relatives, and those from Italy and Spain about becoming unemployed, their finances, their own security, boredom, and Internet access. All of these are significant reasons for stress.

56Perceived stress ratings were notably higher for women, the unemployed, those in a relationship but living apart, and those with lower incomes. In contrast, stress levels were much lower in the elderly. Notably, and in contrast to the results so far, household composition played a major role for self-reported stress, in that the number of adults and the number of children were associated with higher stress scores, i.e. the more people in the household the higher self-reported stress levels.

Depression and anxiety

57Self-reported scores of depression and anxiety were high in all countries. Scores indicating clinically relevant depressive symptoms were well above the norms for all participating countries, with approximately a quarter to one third of participants across countries reporting scores above the clinical cut-off score: France: 25.8 %, Germany: 20.4 %, Italy: 32.3 %, Spain: 31.0 %, Sweden: 25.3 % and Luxembourg: 27.1 %. The same picture occurred for anxiety in that prevalence rates of moderate to severe levels of anxiety (i.e. scores indicating clinically relevant anxiety levels) were well above published norms under “non-pandemic” conditions: 21.84 % in France, 16.39 % in Germany, 31.71 % in Italy, 25.35 % in Spain, 21.35 % in Sweden, and 10.04 % in Luxembourg. The highest depression and anxiety scores were reported by those living in residential or retirement homes. Depression and anxiety were also high for individuals living in larger households, i.e. with 3 or more children, 3 or more additional adults, the younger, women, the unemployed and retired, those not in a relationship, and those with lower incomes.

Loneliness

58Italian and Luxembourgish participants report the highest levels of loneliness, while perceived social support was highest in Luxembourg, followed by Germany and Spain, and lowest in Italy. This shows that one can feel lonely, despite being well supported by one's social network as is the case for Luxembourg. As the level of severity of confinement measures was similar between Italy and Spain, but led to different outcomes, this shows that confinement as such does not predict mental health directly.

59Loneliness was particularly high for singles who were never married or divorced/widowed, and those in a relationship but living apart. Loneliness was also high in individuals living in households with 3 or more children. This may seem counter-intuitive at first sight, but it may reflect the lack of contact with friends, in circumstances where social distancing measures were in place, in addition to the responsibility of having to take care of a large family. Loneliness was also high for those with lower income. Loneliness dropped notably with age. This seemingly counter-intuitive result may be explained by differences in expectation: for a proportion of older people the COVID-19 related social distancing measures may not have made a lot of difference, as they may not have had a lot of contact before. This negative age slope was found in all countries except for Luxembourg, where it resembled an inverted U shape, i.e. the middle-aged reported the highest loneliness scores. The higher levels of loneliness for singles, and for those in a relationship and living apart, were particularly pronounced in France and Luxembourg.