The present study investigated the long-lasting effects of pandemic-related stressors experienced over the past year (i.e. number of days in quarantine and frequency of adverse life events) on young adult’s mental health, specifically examining their relationships with binge eating behaviors, social anxiety, and the emotional impact of pandemic events. In detail, the research aimed to verify the presence of direct and indirect relationships between COVID-19 stressors and binge eating behaviors, hypothesizing the presence of cascade effects via first the emotional impact of events (i.e. avoidance and intrusion of pandemic thoughts), and then social anxiety. Recent studies have shown that subclinical binge eating behaviors have increased during pandemic years (review by [47]). However, there is still limited knowledge about which specific pandemic-related stressors contributed to this increase and which psychological mechanisms underpinned these patterns. Therefore, the present study represents an attempt to further investigate the emotional processes linking pandemic-related stressors to binge eating behaviors in young people.

Subclinical binge eating episodes were reported by 35% of our sample, with 23.8% reporting a low frequency, and 11.5% reporting a weekly or daily frequency. These percentages are slightly higher in comparison to prevalence rates that emerged in pre-pandemic studies (e.g. [11]), but they align with the documented increase in binge eating symptoms among young adults during the COVID-19 period (review by [47, 24]). The number of days spent in quarantine over the past year varied widely in our sample, with most participants reporting to have been isolated at home for a period ranging from one week to two months. These ranges are quite reasonable considering the time frame of data collection (November and December 2021), when Italian people were facing a severe wave of contagions and were recovering after some periods of national lockdown.

According to the results detected in our model, the higher number of days in quarantine during the past year positively predicted intrusive thoughts about the pandemic (but not avoidance of pandemic thoughts), social anxiety symptoms, and frequency of binge eating episodes. These results are in line with recent evidence about the effects of quarantine’s length on depression, anxiety, and stress (e.g., [64]) suggesting that prolonged home confinement due to pandemic issues has been a distressing factor whose impact on mental health should not be undervalued.

First, our findings indicate that the more participants were forced to isolate at home over the past year, the more frequent their intrusive thoughts about the pandemic have been in the current week, suggesting the presence of long-lasting emotional effects comparable to those of emotional trauma [53]. Second, emerging adults exposed to longer quarantine periods also reported more severe social anxiety symptoms in our study, suggesting that the prolonged deprivation of social contacts may have had a role in reinforcing social withdrawal and fear in social contexts. The association of social deprivation with anxiety-related symptoms, already proven in other pandemic research [64], also has a neurobiological foundation in brain changes that occur during long isolation [65]. In line with this evidence, our findings may help to better understand why social anxiety symptoms worsened during the pandemic, as reported by previous studies [31].

Third, our findings appear to support previous research on the impact of home confinement on binge eating symptoms [6, 66], and also provide new evidence for the long-term effects of past isolation on current binge eating frequency. Pandemic studies have offered several possible explanations for the onset of subclinical eating disorder symptoms in the general population during lockdown, suggesting a combined role of food insecurity, disruption of previous lifestyles, long time spent at home, financial difficulties, and health-related fear and anxiety [66]. As suggested by previous research (e.g. [13, 14]), binge eating may indeed be a behavioral response to escape negative emotions and thoughts, in absence of more functional coping strategies. However, there is limited evidence regarding the possible maintenance of binge eating symptomatology in the general population as a long-term effect of lockdown, despite the subsequent easing of restrictions. Nevertheless, some studies have pointed out the increased access to healthcare services for eating disorders in the post-pandemic phase [67]. Thus, based on our findings and previous evidence, it is possible to speculate that once dysfunctional eating patterns emerge during home confinement, their role in emotion regulation may persist even after restrictions are lifted, potentially becoming a chronic response to emotional distress in vulnerable young adults.

Our findings thus partially confirmed the first research hypothesis (H1), detecting significant positive associations between binge eating behaviors and COVID-19 stressors, only with regard to a longer quarantine period. On the other hand, the expected role of pandemic-related adverse life events on binge eating is not significant directly, but only through the indirect effects of emotional symptoms in our model.

The amount and frequency of adverse life events over the past year resulted positively related to two emotional symptoms assessed in the past week: intrusive thinking, and attempts to avoid thoughts, feelings, and memories related to the pandemic. These results suggest that the various adverse life events experienced due to COVID-19 pandemic may have had severe and long-lasting emotional consequences for young people, resembling the emotional patterns associated with other traumatic events, as intrusive thinking and avoidance are generally considered indicative of post-traumatic distress [68]. Previous studies have already found widespread PTSS during the COVID-19 pandemic (e.g. [53, 69]), as well as during previous epidemics (e.g. [70]), but there is limited evidence regarding their long-term course. Thus, our findings may add to the extant knowledge suggesting that the emotional impact of pandemic-related adverse life events may long persist, with intrusive and avoidant symptoms, impairing the emotional well-being of emerging adults for up to one year.

Our second research hypothesis (H2) was also partially confirmed, as intrusive thinking about the pandemic (but not avoidance symptoms) significantly mediated the positive effects of the two COVID-19 stressors on binge eating. There was similar evidence in pre-pandemic research about PTSS in clinical samples (e.g [17]). Specifically, the emotional consequences of traumas played a key role in predicting binge eating among individuals exposed to potentially traumatizing events [23]. Thus, our findings suggest that a similar functioning may be observed for the COVID-19 life events and pandemic quarantine, as both were found to predict intrusive thinking about the adverse pandemic experiences. Intrusive thinking was in turn positively linked to the frequency of binge eating episodes, thus playing a core mediating role in explaining binge eating in response to different COVID-19 stressors. A similar pattern was not found, however, for the avoidance symptoms, which may be indicative instead of different emotional functioning and leading to other mental health outcomes. For example, pandemic research [49] has suggested that the emotional avoidance of pandemic memories may predict alcohol-abusive patterns (rather than dysfunctional eating) in emerging adulthood.

Regarding the third research hypothesis (H3), it was also partially confirmed. Two sequential indirect effects were found in our model, leading from COVID-19-related adverse life events to binge eating, and from the number of days in quarantine to binge eating, via first intrusive thinking, and then social anxiety symptoms. These findings suggest that not only intrusive thinking, but also social anxiety, may play a key role in the emotional pathways leading from negative pandemic experiences to binge eating. We can thus advance some possible interpretations to explain these intrapsychic paths.

First, the pandemic-related stressors in the last year appeared to predict long-lasting intrusive thinking about these experiences, which likely reflects their potential for trauma, as also confirmed in studies about the spread of PTSS during the pandemic [28]. Second, pandemic-related intrusive thinking turned out to predict the severity of social anxiety symptoms in our model. This path can be interpreted in light of pandemic contingencies, during which, for a long time, people were afraid and avoided social contacts due to the concrete risks of contagion [71]. Since social fear and social avoidance are also the core symptoms of social anxiety –despite stemming from different emotional causes– it is possible that the pandemic circumstances may have contributed to the emergence, worsening, or chronicity of these symptoms in vulnerable individuals, as suggested by some studies [31]. Our findings provide support and extend this evidence, suggesting that repetitive thinking about pandemic-related experiences may have contributed to the persistence of subthreshold social anxiety symptoms in vulnerable young people, even long after the pandemic stressors have occurred. Intrusive thoughts and memories about the pandemic may have undermined young people’s self-confidence and social self-esteem, which are common consequences of PTSS [72], thus explaining the presence of social anxiety. Cascade effects of traumatic events on eating disorders have indeed been demonstrated through PTSS, which in turn reduced self-esteem [73].

Third, the resulting social anxiety symptoms appeared to predict more frequent binge eating episodes in young people. They may have indeed managed social anxiety and distress symptoms –stemming from intrusive pandemic-related thoughts– by adopting dysfunctional eating behaviors, which are a behavioral strategy to regulate overwhelming emotions and thoughts, as explained in previous research (i.e. escape theory [14]). Previous studies have indeed demonstrated that binge eating may serve as a self-regulatory strategy for vulnerable people who struggle to control their disturbing thoughts in the presence of poor emotional competence [74]. Thus, binge eating may have served as a dysfunctional strategy to reduce intolerable and incomprehensible distress resulting from intrusive pandemic thoughts and social anxiety. This pattern may have been maintained over time even after the pandemic events had passed.

Despite the innovative findings, this study also has some limitations. First, considering the cross-sectional nature of our data, it is not possible to make causal inferences about the relationships among study variables, and the findings should be exclusively interpreted as correlational associations. Our study evaluated the pandemic experiences over the past year with concurrent and retrospective information, which are helpful but not as informative as longitudinal data could be. Future studies should hopefully verify the emotional patterns that emerged in our findings from a longitudinal perspective.

Second, the absence of pre-pandemic data about study variables (i.e. binge eating and social anxiety) and other mental health conditions (e.g. pre-pandemic diagnoses of eating disorders, anxiety disorders, or other psychiatric diseases) can be considered a limitation, and future research should fill this gap in our model. However, considering the nonclinical nature of our sample, we decided to avoid collecting unnecessary sensitive information and preserve participants’ privacy. Third, other contextual variables related to the pandemic (such as excessive media exposure, decreases in physical activity, or food insecurity during the health emergency) were not assessed, despite their possible role as additional risk factors for mental health.

Fourth, the self-report instruments are always susceptible to social desirability bias, thus sensitive information (e.g. frequency of binge episodes) might have been underreported. However, significant results still emerged in our model, suggesting their validity despite possible underestimation. Fifth, women (69%) were more numerous than men in our sample, maybe due to the higher prevalence of women students in the academic courses where the data were collected (i.e., Psychology, Humanities, Sciences in Social Work). Even if gender differences have been taken under control in our study, the model’s paths might be more representative of women’s emotional functioning. Thus, future studies should replicate our model in well-balanced gender groups.

Finally, the research was conducted in Italy during the specific socio-cultural conditions of the COVID-19 pandemic and included a convenience sample composed of emerging adults attending university lectures. Thus, our results should be considered as exclusively descriptive of the condition of Italian university students during the pandemic, and they may not adequately represent other sociocultural contexts.

Despite these limitations, our findings may contribute to shedding new light on the emotional routes underlying the association between pandemic-related stressors and binge eating in emerging adults, suggesting that some negative events during the COVID-19 pandemic may have had emotional and relational consequences resembling traumatic experiences. To the best of our knowledge, this study is also one of the first evidence about the long-term impact of pandemic adverse events and quarantine on young people’s mental health.

These findings may suggest relevant implications for research, clinical practice, and public health policies, suggesting that the consequences of long home confinement for mental health should be seriously considered. Similarly, more attention should be given to the long-lasting, silent impact of minor adverse events during the pandemic, whose cumulative negative effects may have produced subthreshold traumatic symptoms in vulnerable young adults. More efforts in public health should be made to spread awareness about post-pandemic vulnerability, recognize their emotional consequences for psychophysical well-being, and provide easy access to psychological support for at-risk individuals. Some risk factors for PTSS can also be reduced at a community level, such as controlling the spread of excessively alarming information on mainstream communication channels.

Post-pandemic subthreshold symptoms of social anxiety and binge eating in the general population should be taken seriously, and large-scale prevention and rehabilitation interventions should be envisaged. These programs should be adapted to young adults, to understand the possible consequences of the pandemic years on their emotional and relational functioning, and special attention should be paid to teaching the correct management of intrusive thinking about adverse life events, to reduce their cascade effects on mental health.

As regards future research, starting from our findings, longitudinal studies could be designed to follow the long-term course of post-pandemic distress in the next years and extend the age range of observation. For example, longitudinal studies may be targeted at young people who experienced the COVID-19 pandemic during their early and middle adolescence, the typical age of onset for binge eating symptoms and social anxiety disorder. Also, the possible changes in BMI that occurred during the pandemic should be assessed in future research, as during adolescence and early adulthood the emergence of body image issues is a risk factor for social anxiety and problem eating behaviors. Future directions of our study should also consider other emotional routes as possible alternative mediators in our model, such for example symptoms of generalized anxiety.