Who develops long COVID? Longitudinal pre-pandemic predictors of long COVID and symptom clusters in a representative Dutch population.

OBJECTIVES: Prior studies show that long COVID has a heterogeneous presentation. Whether specific risk factors are related to subclusters of long COVID remains unknown. This study aimed to determine pre-pandemic predictors of long COVID and symptom clustering. METHODS: 3022 participants of a panel representative of the Dutch population completed an online survey about long COVID symptoms. Data was merged to 2018/2019 panel data covering sociodemographic, medical, and psychosocial predictors. A total of 415 participants were classified as having long COVID. K-means clustering was used to identify patient clusters. Multivariate and lasso regression was used to identify relevant predictors compared to a COVID-19 positive control group. RESULTS: Predictors of long COVID included Western ethnicity, BMI, chronic disease, COVID-19 reinfections, severity, and symptoms, lower self-esteem, and higher positive affect (AUC=0.80, 95%CI 0.73-0.86). Four clusters were identified: a low and a high symptom severity cluster, a smell-taste and respiratory symptoms cluster, and a neuro-cognitive, psychosocial, and inflammatory symptom cluster. Predictors for the different clusters included regular health complaints, healthcare use, fear of COVID-19, anxiety, depressive symptoms, and neuroticism. CONCLUSIONS: A combination of sociodemographic, medical, and psychosocial factors predicted long COVID. Heterogenous symptom clusters suggest that there are different phenotypes of long COVID presentation.

Long COVID is not a uniform syndrome: Evidence from person-level symptom clusters using latent class analysis.

BACKGROUND: The current study aims to enhance insight into the heterogeneity of long COVID by identifying symptom clusters and associated socio-demographic and health determinants. METHODS: A total of 458 participants (Mage 36.0 ± 11.9; 46.5% male) with persistent symptoms after COVID-19 completed an online self-report questionnaire including a 114-item symptom list. First, a k-means clustering analysis was performed to investigate overall clustering patterns and identify symptoms that provided meaningful distinctions between clusters. Next, a step-three latent class analysis (LCA) was performed based on these distinctive symptoms to analyze person-centered clusters. Finally, multinominal logistic models were used to identify determinants associated with the symptom clusters. RESULTS: From a 5-cluster solution obtained from k-means clustering, 30 distinctive symptoms were selected. Using LCA, six symptom classes were identified: moderate (20.7%) and high (20.7%) inflammatory symptoms, moderate malaise-neurocognitive symptoms (18.3%), high malaise-neurocognitive-psychosocial symptoms (17.0%), low-overall symptoms (13.3%) and high overall symptoms (9.8%). Sex, age, employment, COVID-19 suspicion, COVID-19 severity, number of acute COVID-19 symptoms, long COVID symptom duration, long COVID diagnosis, and impact of long COVID were associated with the different symptom clusters. CONCLUSIONS: The current study's findings characterize the heterogeneity in long COVID symptoms and underscore the importance of identifying determinants of different symptom clusters.

Managing Fear During Pandemics: Risks and Opportunities.

Fear is an emotion triggered by the perception of danger and motivates safety behaviors. Within the context of the COVID-19 pandemic, there were ample danger cues (e.g., images of patients on ventilators) and a high need for people to use appropriate safety behaviors (e.g., social distancing). Given this central role of fear within the context of a pandemic, it is important to review some of the emerging findings and lessons learned during the COVID-19 pandemic and their implications for managing fear. We highlight factors that determine fear (i.e., proximity, predictability, and controllability) and review several adaptive and maladaptive consequences of fear of COVID-19 (e.g., following governmental health policies and panic buying). Finally, we provide directions for future research and make policy recommendations that can promote adequate health behaviors and limit the negative consequences of fear during pandemics.

Fear of COVID-19: Data of a large longitudinal survey conducted between March 2020 and June 2021.

Research indicates that fear was an important factor in determining individual responses to COVID-19, predicting relevant behaviors such as compliance to preventive measures (e.g., hand washing) and stress reactions (e.g., poor sleep quality). Given this central role of fear, it is important to understand more about its temporal changes during the COVID-19 pandemic. This article describes a publicly available dataset that contains longitudinal assessment of fear of COVID-19 and other relevant constructs during the first 15 months of the pandemic. Particularly, the dataset contains data from two different samples. The first sample consists predominantly of Dutch respondents (N = 439) who completed a cross-sectional survey in March 2020. The second sample consists of a large-scale longitudinal survey (N = 2000 at T1), including respondents with a broad range of nationalities (though predominantly residing in Europe and North America; 95.6%). The respondents of the second sample completed the survey between April 2020 and August 2020 using the Prolific data collection platform. In addition, one follow-up assessment was completed in June 2021. The measures included in the survey were fear of COVID-19, demographic information (age, gender, country of residence, education level, and working in healthcare), anxious traits (i.e., intolerance of uncertainty, health anxiety, and worrying), media use, self-rated health, perceived ability to prevent infection, and perceived risk for loved ones. Additionally, at the follow-up assessment in June 2021, respondents were asked whether they were vaccinated against COVID-19 or were planning to get vaccinated. The datafiles of this study have been made available through the Open Science Framework and can be freely reused by psychologists, social scientists, and other researchers who wish to investigate the development, correlates, and consequences of fear of COVID-19.

Pandemic panic? Results of a 14-month longitudinal study on fear of COVID-19.

BACKGROUND: Fear is an evolutionary adaptive emotion that serves to protect the organism from harm. Once a threat diminishes, fear should also dissipate as otherwise fear may become chronic and pathological. While actual threat of the COVID-19 pandemic (i.e., number of infections, hospitalizations, and deaths) has substantially varied over the course of the pandemic, it remains unclear whether (subjective) fear has followed a similar pattern. METHOD: To examine the development of fear of COVID-19 during the pandemic and investigate potential predictors of chronic fear, we conducted a large online longitudinal study (N = 2000) using the Prolific platform between April 2020 and June 2021. Participants were voluntary response samples and consisted of residents of 34 different countries. The Fear of the Coronavirus Questionnaire (FCQ) and several other demographic and psychological measures were completed monthly. RESULTS: Overall, we find that fear steadily decreased since April 2020. Additional analyses showed that elevated fear was predicted by region (i.e., North America > Europe), anxious traits, gender, risks for loved ones, general health, and media use. LIMITATIONS: The interpretation of the results of this study is limited by the non-representativeness of the sample and the lack of data points between August 2020 and June 2021. CONCLUSIONS: This study helps to characterize the trajectory of fear levels throughout the COVID-19 pandemic and establish several relevant predictors of increased fear.

Boosting long-term effects of degraded memories via acute stress.

Combining recall of an emotional memory with simultaneous horizontal eye movements (i.e., Recall + EM) reduces memory aversiveness. However, the long-term persistence of this effect is inconsistent across studies. Given that stress may aid in the consolidation of memories, we examined whether acute stress can boost the long-term effects of degraded memories. To test this, participants recalled two negative memories, which were assigned to a Recall + EM or Recall Only condition. Before and after each intervention they rated memory aversiveness (i.e., immediate effects) followed by a stress-induction or control procedure. After a 24h-period, participants rated each memory again (i.e., long-term effects). We found that Recall + EM produces immediate effects but that these effects dissolve over time. Moreover, acute stress did not boost potential long-term effects of Recall + EM. Degraded memories were not retained better by applying stress. We discuss these results and how long-term effectiveness may still be achieved.

The relationship between Intolerance of Uncertainty and conditioned fear acquisition: Evidence from a large sample.

Despite being considered a valid model for the etiology of anxiety disorders, the fear conditioning paradigm does not always show clear correlations with anxious personality traits that constitute risk factors for the development of anxiety disorders. This may in part due to error variance and the fact that fear conditioning studies are typically underpowered to investigate inter-individual differences. In the current study, we focus on the relationship between conditioned fear acquisition and Intolerance of Uncertainty (IU). In a re-analysis of a large previous study (N = 120), which was conducted using a healthy student sample and a partial reinforcement procedure (75%) with words as Conditioned Stimuli (CSs), the relationship between IU and several outcome measures (i.e., fear ratings, expectancy ratings, skin conductance responses, and startle responses) during fear acquisition was examined. We find that IU is positively related to fear ratings towards the CS+ (r = 0.29), even when controlling for the shared variance with trait anxiety. Furthermore, we find a subtle relationship between IU and startle responses to the CS- (r = -0.23), though this correlation did not survive correction for the shared variance with trait anxiety. Taken together, we replicate some of the correlations previously reported in the literature. However, we recommend that future studies employ even larger samples and more advanced statistical techniques such as structural equation modelling to investigate the correlations between fear acquisition indices and anxious traits in a fine-grained manner.

Fear of COVID-19 predicts vaccination willingness 14 months later.

Vaccines are an important tool for governments and health agencies to contain and curb the Coronavirus Disease-19 (COVID-19) pandemic. However, despite their effectiveness and safeness, a substantial portion of the population worldwide is hesitant to get vaccinated. In the current study, we examined whether fear of COVID-19 predicts vaccination willingness. In a longitudinal study (N = 938), fear for COVID-19 was assessed in April 2020 and vaccination willingness was measured in June 2021. Approximately 11% of our sample indicated that they were not willing to get vaccinated. Results of a logistic regression showed that increased fear of COVID-19 predicts vaccination willingness 14 months later, even when controlling for several anxious personality traits, infection control perceptions, risks for loved ones, self-rated health, previous infection, media use, and demographic variables. These results show that fear of COVID-19 is a relevant construct to consider for predicting and possibly influencing vaccination willingness. Nonetheless, sensitivity and specificity of fear of COVID-19 to predict vaccination willingness were quite low and only became slightly better when fear of COVID-19 was measured concurrently. This indicates that other potential factors, such as perceived risks of the vaccines, probably also play a role in explaining vaccination willingness.

The effectiveness of dual-task interventions for modulating emotional memories in the laboratory: A meta-analysis.

Dual-tasks (e.g., making horizontal eye-movements) while recollecting a memory are often used both in the lab and the clinic (such as in EMDR therapy) to attenuate emotional memories and intrusive mental images. According to working memory theory, dual-task interventions are effective because they limit cognitive resources available for the processing of emotional memories. However, there is still ongoing debate about the extent to which and under what conditions dual-task interventions are effective to interfere with emotional memories. In this meta-analysis, we assessed k = 53 laboratory studies investigating the effects of dual-task interventions on negative and positive memories. The effects were measured with the raw mean reduction in vividness and emotionality self-report ratings of emotional memories before compared to after the intervention on 100-point rating scales. Results showed that the dual-task interventions made both negative and positive memories less vivid (mean reduction negative images = 9.18, 95% CI [7.06, 11.29]; mean reduction positive images = 11.73, 95% CI [8.59, 14.86]) and less emotional (mean reduction negative images = 6.22, 95% CI [4.50, 7.94]; mean reduction positive images = 6.71, 95% CI [2.21, 11.20]). Several moderators were tested and are discussed in the light of working memory theory.

Conceptual fear generalization gradients and their relationship with anxious traits: Results from a Registered Report.

A hallmark symptom of fear and anxiety disorder is generalization of fear to essentially innocuous stimuli and situations. Such generalization can occur through both perceptual and conceptually similarities. Recent studies indicate that perceptual generalization is inflated in anxiety patients and individuals prone to develop anxiety disorders, suggesting that perceptual generalization may be involved in the etiology of anxiety disorders. In the current Registered Report, we wanted to address whether conceptual generalization is potentially implicated in the development of anxiety disorders as well. Therefore, we used a novel paradigm in which the Dutch word mini [tiny] or enorm [enormous] was paired with an electric shock and assessed fear to the conceptually related words klein [small], medium [medium], and groot [large]. The sample (N = 120) consisted of healthy university students. As hypothesized, we observed clear conceptual fear generalization gradients using both self-report and psychophysiological measures. However, in contrast to our expectations, these conceptual generalization gradients were not correlated with different anxious traits (i.e., trait anxiety, intolerance of uncertainty, and behavioral inhibition). These results show that fear can generalize conceptually along a gradient, without requiring perceptual errors as postulated by traditional models of fear generalization. Instead, our results correspond well with inferential reasoning theories of fear generalization. Additionally, we discuss potential reasons for the absence of the expected correlations between conceptual fear generalization and anxious traits, such as restricted variability in both the generalization task and the sample. We conclude that the paradigm has promise for further research on conceptual fear generalization.

Does an unconditioned stimulus memory devaluation procedure decrease disgust memories and conditioned disgust? Results of two laboratory studies.

Research has demonstrated that disgust can be installed through classical conditioning by pairing neutral conditioned stimuli (CSs) with disgusting unconditioned stimuli (USs). Disgust has been argued to play an important role in maintaining fear-related disorders. This maintaining role may be explained by conditioned disgust being less sensitive to extinction (i.e., experiencing the CS in the absence of the US). Promising alternatives to extinction training are procedures that focus on the devaluation of US memory representations. In the current study, we investigated whether such devaluation procedures can be successful to counter conditioned disgust. We conducted two laboratory studies (N = 120 and N = 51) in which disgust was conditioned using audio-visual USs. Memory representations of the USs were devalued by having participants recall these USs while they performed a taxing eye-movement task or executed one of several control tasks. The results showed successful conditioned disgust acquisition. However, no strong evidence was obtained that an US memory devaluation procedure modulates disgust memory and diminishes conditioned disgust as indicated by subjective, behavioral, or psychophysiological measures. We discuss the relevance of our results for methodological improvements regarding US memory devaluation procedures and disgust conditioning.

Verbal suggestions fail to modulate expectations about the effectiveness of a laboratory model of EMDR therapy: Results of two preregistered studies.

BACKGROUND AND OBJECTIVES: For many psychotherapies, like Eye Movement and Desensitization Reprocessing (EMDR) therapy, there is an ongoing discussion about the role of specific versus non-specific mechanisms in their effectiveness However, experimental research directly examining the potential role of non-specific mechanisms is scarce. Here, we address the role of a non-specific factor that is often put forward for EMDR, namely treatment effectiveness expectations, within a laboratory model of EMDR therapy. METHODS: In a lab-based (N = 96) and an online experiment (N = 173), we gave participants verbal instructions to manipulate their treatment expectations. Instructions emphasized EMDR's effectiveness or ineffectiveness. Then, participants were asked to recollect an unpleasant autobiographical memory with or without making eye-movements. RESULTS: In line with previous studies, we found significant reductions of reported vividness and emotionality of negative autobiographical memories in the eye-movements condition. These reductions did not differ between the verbal suggestions conditions in both experiments, suggesting a limited effect of treatment effectiveness suggestions. LIMITATIONS: Treatment effectiveness expectations were not successfully manipulated by the suggestions manipulation. This suggests that treatment expectations may be more difficult to influence than anticipated, thus limiting the interpretation of our findings. CONCLUSIONS: These findings tentatively corroborate the results of two earlier reports, suggesting that the effects of verbal suggestions about treatment effectiveness in a laboratory model of EMDR therapy may be limited.

The role of intolerance of uncertainty in classical threat conditioning: Recent developments and directions for future research.

Intolerance of uncertainty (IU), the tendency to find uncertainty aversive, is an important transdiagnostic dimension in mental health disorders. Over the last decade, there has been a surge of research on the role of IU in classical threat conditioning procedures, which serve as analogues to the development, treatment, and relapse of anxiety, obsessive-compulsive, and trauma- and stressor-related disorders. This review provides an overview of the existing literature on IU in classical threat conditioning procedures. The review integrates findings based on the shared or discrete parameters of uncertainty embedded within classical threat conditioning procedures. Under periods of unexpected uncertainty, where threat and safety contingencies change, high IU, over other self-reported measures of anxiety, is specifically associated with poorer threat extinction learning and retention, as well as overgeneralisation. Under periods of estimation and expected uncertainty, where the parameters of uncertainty are being learned or have been learned, such as threat acquisition training and avoidance learning, the findings are mixed for IU. These findings provide evidence that individual differences in IU play a significant role in maintaining learned fear and anxiety, particularly under volatile environments. Recommendations for future research are outlined, with discussion focusing on how parameters of uncertainty can be better defined to capture how IU is involved in the maintenance of learned fear and anxiety. Such work will be crucial for understanding the role of IU in neurobiological models of uncertainty-based maintenance of fear and anxiety and inform translational work aiming to improve the diagnosis and treatment of relevant psychopathology.

The latent and item structure of COVID-19 fear: A comparison of four COVID-19 fear questionnaires using SEM and network analyses.

Since the outbreak of the coronavirus disease (COVID-19), several reports have shown that fear relating to COVID-19 has sharply increased. To measure fear of COVID-19, various questionnaires have been developed in parallel. However, fear concerning COVID-19 is not necessarily a uniform construct and the different questionnaires may cover diverse aspects. To examine the underlying structure of fear of COVID-19, we conducted structural equation modelling and network analyses on four scales in an online convenience sample (N = 829). Particularly, the Fear of COVID-19 Scale (Ahorsu et al., 2020), the Fear of the Coronavirus Questionnaire (Mertens et al., 2020), and the COVID Stress Scales (Taylor, Landry, Paluszek, Fergus et al., 2020, Taylor, Landry, Paluszek, Rachor et al., 2020) were included in our study, along with a new scale that also assessed socio-economic worries relating to COVID-19. We found that fear of COVID-19 was best classified into four clusters: Fear of health-related consequences, fear of supplies shortages and xenophobia, fear about socio-economic consequences, and symptoms of fear (e.g., compulsions, nightmares). We also find that a central cluster of items centered on fear of health, which likely represents the core of fear of COVID-19. These results help to characterize fear due to COVID-19 and inform future research.

Optimism, mindfulness, and resilience as potential protective factors for the mental health consequences of fear of the coronavirus.

The COVID-19 pandemic has a substantial impact on mental health. Prior reports have shown that depression, anxiety, and stress have increased throughout the pandemic. Nonetheless, not everyone is affected by these negative consequences and some people may be relatively unaffected. In this online study in a predominantly Dutch and Belgian sample (N = 546), we investigated whether positive personality traits such as optimism, mindfulness, and resilience may protect against the negative mental health consequences (i.e., fear of the coronavirus, depression, stress, and anxiety) of the COVID-19 pandemic. We found that fear of COVID-19 was related to higher depression, stress, and anxiety. However, for participants scoring high on mindfulness, optimism, and resilience, this relationship was weakened. In addition to these findings, we present the results of network analyses to explore the network structure between these constructs. These results help to identify possible ways through which psychological well-being can be promoted during the COVID-19 pandemic.

Intolerance of uncertainty and threat reversal: A conceptual replication of Morriss et al. (2019).

The ability to update responding to threat cues is an important adaptive ability. Recently, Morriss et al. (2019) demonstrated that participants scoring high in Intolerance of Uncertainty (IU) were more capable of threat reversal. The current report aimed to conceptually replicate these results of Morriss et al. (2019) in an independent sample using a comparable paradigm (n = 102). Following a threat conditioning phase, participants were told that cues associated with threat and safety from electric shock would reverse. Responding was measured with skin conductance and fear potentiated startle. We failed to conceptually replicate the results of Morriss et al. (2019). Instead, we found that, for participants who received precise contingency instructions prior to acquisition, lower IUS (controlling for STAI-T) relative to higher IUS was associated with greater threat reversal, indexed via skin conductance responses. These results suggest that IU and contingency instructions differentially modulate the course of threat reversal.

Human fear conditioning is moderated by stimulus contingency instructions.

Recent research findings indicate that human fear conditioning is affected by instructions, particularly those concerning the contingency between the conditioned stimulus (CS) and the unconditioned stimulus (US). However, whether or not such instructions were provided to participants often remains unsaid in fear conditioning studies. In the current study (N = 102), we investigated whether conditioned fear acquisition depends on CS-US contingency instructions. Participants were randomly assigned to one of three groups. The first group was instructed about the precise CS-US contingency before conditioning. The second group was instructed to discover the CS-US contingency. The third group did not receive any contingency instructions. We found facilitated fear acquisition (using skin conductance and startle) and increased contingency awareness in the first and second group compared to the third group. Furthermore, contingency reversal instructions immediately reversed conditioned responses. Based on these results, we advise to systematically report the contingency instructions used in fear conditioning research.

Induction of conditioned avoidance via mental imagery.

There is a growing interest on how mental imagery may be involved in the onset and maintenance of anxiety-related disorders. Here, we used an experimental design to investigate whether a key symptom across anxiety-related disorders, namely avoidance, can be induced via mental imagery. Healthy participants first learned that one neutral stimulus (A) was associated with a mild electric shock and two other neutral stimuli (B and C) were not. They then learned to cancel the shock when A was presented, by pressing a button on a keyboard ('behavioral avoidance'). Next, they were asked to imagine that stimulus B was followed by the shock (i.e., without actual B or shock presentations; Experiment 1; N = 66) or they were shown B and asked to imagine the shock (i.e., without actual shock presentations; Experiment 2; N = 60). Finally, in the test phase, they were shown each of the three stimuli (without the shock) and given the opportunity to make the avoidance response. Results showed that participants tended to avoid B in the test phase in Experiment 1, even though it had never been presented with the shock but not in Experiment 2. We discuss how the findings may explain the acquisition of avoidance in the presentation of innocuousstimuli across anxiety-related disorders.