Move more today, sleep better tonight? Daily associations between physical activity and sedentary behavior with sleep among young adults with and without insomnia symptoms.

OBJECTIVE: At the between-person level, it is well-documented that individuals with more physical activity (PA) and less sedentary behavior (SB) tend to have better sleep outcomes than their peers. However, the associations at the within-person level remain unclear. This study investigated the daily associations between PA and SB with nighttime sleep among young adults with and without insomnia symptoms. METHODS: Data was collected through activity trackers and online questionnaires for 7 consecutive days among 147 university students, including time spent on moderate to vigorous physical activity (MVPA), light physical activity (LPA), and SB, along with sleep duration, sleep efficiency, and sleep quality. Participants were classified into two subgroups according to the presence of insomnia symptoms, which were determined by a self-reported insomnia scale. Multilevel compositional data analysis was conducted on the total sample, and separately on subsamples characterized by the presence and absence of insomnia symptoms. RESULTS: In the total sample and subsample without insomnia symptoms, substitutions among MVPA, LPA, and SB were not associated with changes in sleep outcomes at the daily level. However, in the subsample with insomnia symptoms, days with more MVPA or SB and less LPA were associated with higher sleep efficiency, while days with more LPA at the expense of MVPA or SB were associated with lower sleep efficiency. CONCLUSIONS: For young adults with insomnia symptoms, replacing LPA with MVPA on a given day may improve their sleep efficiency that night.

Psychosocial determinants of handwashing and physical distancing behaviour during the COVID-19 pandemic in the Netherlands: A longitudinal analysis.

OBJECTIVES: Physical distancing and handwashing can be important infection prevention measures during an infectious disease outbreak such as the COVID-19 pandemic. To stimulate these behaviours, knowledge of psychosocial determinants as well as contextual factors is vital. We present longitudinal, within-person analyses of the impact of contextual and psychosocial factors on handwashing and distancing behaviour. DESIGN: We used individual-level data (186,490 participants completing 971,899 surveys) from the Corona Behavioural Unit COVID-19 Cohort, a dynamic cohort study conducted during 26 months of the COVID-19 pandemic in the Netherlands. METHODS: Fixed-effects models were employed to estimate within-person associations between psychosocial factors and behaviour, combined with main and moderating effects of contextual factors. RESULTS: Pandemic severity was associated with more handwashing and distancing behaviour, while the duration of the pandemic had little effect. Within-person changes in response efficacy were most relevant for changes in both handwashing and distancing behaviour, while self-efficacy, descriptive norms and perceived severity of infecting others affected behaviour indirectly. These effects were stable over time. Associations were larger in cross-sectional models, indicating that such models tend to overestimate effects. CONCLUSIONS: Our study highlights the importance of longitudinal data and within-person models to detect possible causal associations. The results suggest that during an outbreak, government and public health professionals should clearly communicate the severity of the pandemic (e.g., hospitalization rates) and the effectiveness of recommended prevention measures in reducing that risk; and seek to improve people's capabilities and opportunities to adhere to guidelines, for example, by modifying the environment.

Within-Person Dynamics of Job Boredom and Counterproductive Work Behavior: A Latent Change Score Modeling Approach.

Job boredom is one of the most common negative affective states experienced in the workplace, yet also among the least well-understood. One stream of research suggests that employees frequently react to job boredom by engaging in counterproductive work behaviors (CWB). However, recent studies show the converse-that engaging in CWB relates to job boredom. As studies on the job boredom-CWB relationship primarily have been cross-sectional and at the between-person level of analysis, the directionality between these constructs remains in question. Therefore, research examining the within-person dynamics of job boredom and CWB within a short timeframe is needed. In the current study, we explore whether job boredom influences subsequent changes in CWB and vice versa. We examined these relationships using latent change score (LCS) modeling with 10-day experience sampling data (N = 120 individuals providing 1,161 observations). Findings supported a reciprocal relationship. Employees' level of job boredom on a given day was associated with a subsequent increase in CWB on the next day, and the level of CWB on a given day was associated with a subsequent increase in job boredom on the next day. We discuss the implications of our findings, study limitations, and future research directions.

Daily Limited Future Time Perspective Is Associated with More Health Behavior Within Older Adults.

OBJECTIVE: Cross-sectional studies suggest that individuals who perceive a broader future horizon may be more likely to consider the future consequences of their actions and, as a result, engage in healthy lifestyle behaviors. However, research has yet to consider how this association plays out on the daily level. METHOD: The present study used daily diary data from a sample of 198 older adults aged 60 years and older (M = 63.34, SD = 3.29) to investigate the relationship between daily future time perspective (FTP) and daily health behavior. Participants reported on sociodemographic characteristics during baseline surveys and completed daily diary measures of FTP and health behavior (e.g., nutrition, exercise, social/leisure activity) across 14 days. Multilevel modeling was used to examine within- and between-person associations between daily FTP and health behavior. RESULTS: Daily FTP was significantly associated with daily health behavior at the within- but not at the between-person level. Counter to past cross-sectional work, results revealed that individuals showed increased engagement in health behavior on days when they reported a more limited FTP. DISCUSSION: Findings highlight the importance of moving beyond the between-person level to consider how FTP fluctuates from day-to-day and relates to health behavior in everyday life. Older adults who view a more limited time horizon may be motivated to increase that future through healthier activities.

Reversions mask the contribution of adaptive evolution in microbiomes.

When examining bacterial genomes for evidence of past selection, the results depend heavily on the mutational distance between chosen genomes. Even within a bacterial species, genomes separated by larger mutational distances exhibit stronger evidence of purifying selection as assessed by dN/dS, the normalized ratio of nonsynonymous to synonymous mutations. Here, we show that the classical interpretation of this scale dependence, weak purifying selection, leads to problematic mutation accumulation when applied to available gut microbiome data. We propose an alternative, adaptive reversion model with opposite implications for dynamical intuition and applications of dN/dS. Reversions that occur and sweep within-host populations are nearly guaranteed in microbiomes due to large population sizes, short generation times, and variable environments. Using analytical and simulation approaches, we show that adaptive reversion can explain the dN/dS decay given only dozens of locally fluctuating selective pressures, which is realistic in the context of Bacteroides genomes. The success of the adaptive reversion model argues for interpreting low values of dN/dS obtained from long timescales with caution as they may emerge even when adaptive sweeps are frequent. Our work thus inverts the interpretation of an old observation in bacterial evolution, illustrates the potential of mutational reversions to shape genomic landscapes over time, and highlights the importance of studying bacterial genomic evolution on short timescales.

Search efforts and face recognition: the role of expectations of encounter and within-person variability in prospective person memory.

People perform poorly at sighting missing and wanted persons in simulated searches due to attention and face recognition failures. We manipulated participants' expectations of encountering a target person and the within-person variability of the targets' photographs studied in a laboratory-based and a field-based prospective person memory task. We hypothesized that within-person variability and expectations of encounter would impact prospective person memory performance, and that expectations would interact with within-person variability to mitigate the effect of variability. Surprisingly, low within-person variability resulted in better performance on the search task than high within-person variability in Experiment one possibly due to the study-test images being rated as more similar in the low variability condition. We found the expected effect of high variability producing more hits for the target whose study-test images were equally similar across variability conditions. There was no effect of variability in Experiment two. Expectations affected performance only in the field-based study (Experiment two), possibly because performance is typically poor in field-based studies. Our research demonstrates some nuance to the effect of within-person variability on search performance and extends existing research demonstrating expectations affect search performance.

Longitudinal Associations between Future Time Perspective, Sleep Problems, and Depressive Symptoms among Chinese College Students: Between- and within-Person Effects.

Depressive symptoms and sleep problems are extremely prevalent in adolescence, and future time perspective has been found to be strongly associated with them. However, little is known about the longitudinal relationship and the temporal dynamics of future time perspective, sleep problems, and depressive symptoms. Moreover, it is unclear whether sleep problems mediate the associations between future time perspective and depressive symptoms. To address this gap, a one-year longitudinal study was performed using data collected at three waves from 622 Chinese college students (aged 17-22 years, Mage = 18.16, SD = 1.49, 46.95% males). The results of cross-lagged panel models showed a bidirectional relationship between future time perspective and depressive symptoms, and that sleep problems were a mediating mechanism for these relationships. The results of random intercept cross-lagged panel models showed that at the within-person level, the change of sleep problems and depressive symptoms significantly affected the development of future time perspective, but the reverse effect not significant. Moreover, sleep problems mediated the within-person effect of depressive symptoms on future time perspective. These findings deepen the understanding of the longitudinal relationship between future time perspective, sleep problems and depressive symptoms, and emphasize the important role of sleep health in adolescent mental health and future development.

Unraveling the optimal balance of problem-related affective experiences and need satisfaction in cognitive-behavioral therapy: A response surface analysis.

Objective: Although therapists are encouraged to balance emotionally involving work on the patient's problems with need satisfaction in therapy sessions, effects of this balance have rarely been studied empirically. Hence, we examined congruence effects between problem-related affective and need-satisfying experiences in cognitive-behavioral therapy (CBT). Method: 165 distressed family caregivers rated problem-related affective experiences, need-satisfying experiences comprising self-esteem, positive interpersonal, and control experiences, as well as coping experiences after 12 CBT sessions. We examined within-person congruence effects of problem-related affective and need-satisfying experiences on subsequent coping in multilevel response surface analysis. Further, we included between-person problem-related affective and need-satisfying experiences and pretreatment depression and anxiety as moderators of within-person effects. Results: A slight predominance of self-esteem over problem-related affective experiences as well as exact correspondence between problem-related affective and both interpersonal and control experiences was most predictive of coping. Between-person moderators supported a cross-level balance heuristic of problem-related affective and self-esteem experiences. Finally, a stronger emphasis on self-esteem and interpersonal over problem-related affective experiences proved more beneficial for patients with high anxiety and low depression. Conclusions: The findings highlight the importance of balancing problem-related affective and need-satisfying experiences in CBT and provide insights into how balancing may be tailored to specific patients.

Bi-Directional and Time-Lagged Associations between Engagement and Mental Health Symptoms in a Group Mindfulness-Based Mental Health Intervention.

There is a high need for accessible avenues for improving mental health among emerging adults, particularly on college campuses. Mindfulness-based intervention (MBI) is a promising avenue for reducing mental health symptoms, but initial discomforts associated with MBI may cause symptoms to fluctuate before decreasing, which presents a barrier to engagement with mindfulness on a daily basis. Consistent mindfulness practice is key for forming habits related to MBI, and engagement with mindfulness at home, including between intervention sessions, is an important predictor of mental health outcomes. Research suggests that mental health symptoms may serve as barriers to their own treatment. Thus, it is important to understand how mental health symptom levels impact adherence to treatment protocols. To improve understanding of symptom-specific barriers to treatment and engagement with mindfulness, the present study collected daily diary surveys about engagement with mindfulness and mental health symptoms from a sample of 62 adults recruited to participate in a six-week mindfulness intervention. We explored mental health symptoms as a predictor of engagement with MBI at the mean level and whether within-person variability in symptoms predicted same-day or time-lagged changes in engagement via mixed-effects associations. Using heterogeneous location scale models, we further explored whether erraticism in either mental health symptoms or engagement with mindfulness predicted the other and if outcomes of the mindfulness intervention were homogeneous among subjects. Results showed that bi-directional and time-lagged associations exist between symptoms and engagement, indicating that there is a nuanced temporal and reciprocal relationship between engagement with mindfulness and mental health symptoms. Daily within-person elevations in engagement with mindfulness were associated with concurrent improvements in mental health but prospective increases in mental health symptoms. We also found that higher engagement (over personal averages) was not consistently associated with improvements in mental health across the sample but was instead associated with greater heterogeneity in outcomes. We also found that increases in mental health symptoms (over personal averages), as well as higher average levels of mental health symptoms, were both associated with lower levels of engagement in the mindfulness treatment protocol.

Increases in sense of purpose predict future positive changes in personality traits.

This longitudinal study examined the reciprocal relationship between the Big Five personality traits and sense of purpose over a 13-year period using a nationally representative sample of American adults (N = 11,010). The random intercept cross-lagged panel model revealed unidirectional effects: increases in sense of purpose predicted subsequent increases in openness, agreeableness, conscientiousness, and extraversion, as well as decreases in neuroticism. Conversely, changes in personality traits did not predict future changes in sense of purpose. One potential mechanism underlying this effect might involve the link between sense of purpose and optimal self-regulatory processes and outcomes, such as successful planning, goal-directed behaviour, and self-control, which promote gradual positive changes in personality traits. Another plausible mechanism may be the association between purpose and improved subjective well-being and reduced psychological distress, which have been found to predict positive changes in personality traits. These findings challenge previous research that has interpreted cross-sectional associations as evidence that personality traits are predictive of purpose, rather than the other way around. The findings that intentionally cultivating a strong sense of purpose may facilitate positive personality change in adulthood.

Estimating nonlinear effects of random slopes: A comparison of multilevel structural equation modeling with a two-step, a single-indicator, and a plausible values approach.

Multilevel structural equation modeling (MSEM) is a statistical framework of major relevance for research concerned with people's intrapersonal dynamics. An application domain that is rapidly gaining relevance is the study of individual differences in the within-person association (WPA) of variables that fluctuate over time. For instance, an individual's social reactivity - their emotional response to social situations - can be represented as the association between repeated measurements of the individual's social interaction quantity and momentary well-being. MSEM allows researchers to investigate the associations between WPAs and person-level outcome variables (e.g., life satisfaction) by specifying the WPAs as random slopes in the structural equation on level 1 and using the latent representations of the slopes to predict outcomes on level 2. Here, we are concerned with the case in which a researcher is interested in nonlinear effects of WPAs on person-level outcomes - a U-shaped effect of a WPA, a moderation effect of two WPAs, or an effect of congruence between two WPAs - such that the corresponding MSEM includes latent interactions between random slopes. We evaluate the nonlinear MSEM approach for the three classes of nonlinear effects (U-shaped, moderation, congruence) and compare it with three simpler approaches: a simple two-step approach, a single-indicator approach, and a plausible values approach. We use a simulation study to compare the approaches on accuracy of parameter estimates and inference. We derive recommendations for practice and provide code templates and an illustrative example to help researchers implement the approaches.

Reciprocal relations between dimensions of attention-deficit/hyperactivity and anxiety disorders from preschool age to adolescence: sex differences in a birth cohort sample.

BACKGROUND: Symptoms of anxiety and attention-deficit/hyperactivity disorder (ADHD) are prospectively related from childhood to adolescence. However, whether the two dimensions of ADHD-inattention and hyperactivity-impulsivity-are differentially related to anxiety and whether there are developmental and sex/gender differences in these relations are unknown. METHODS: Two birth cohorts of Norwegian children were assessed biennially from ages 4 to 16 (N = 1,077; 49% girls) with diagnostic parent interviews used to assess symptoms of anxiety and ADHD. Data were analyzed using a random intercept cross-lagged panel model, adjusting for all unobserved time-invariant confounding effects. RESULTS: In girls, increased inattention, but not hyperactivity-impulsivity, predicted increased anxiety 2 years later across all time-points and increased anxiety at ages 12 and 14 predicted increased inattention but not hyperactivity-impulsivity. In boys, increased hyperactivity-impulsivity at ages 6 and 8, but not increased inattention, predicted increased anxiety 2 years later, whereas increased anxiety did not predict increased inattention or hyperactivity-impulsivity. CONCLUSIONS: The two ADHD dimensions were differentially related to anxiety, and the relations were sex-specific. In girls, inattention may be involved in the development of anxiety throughout childhood and adolescence and anxiety may contribute to girls developing more inattention beginning in early adolescence. In boys, hyperactivity-impulsivity may be involved in the development of anxiety during the early school years. Effective treatment of inattention symptoms in girls may reduce anxiety risk at all time-points, while addressing anxiety may decrease inattention during adolescence. Similarly, treating hyperactivity-impulsivity may reduce anxiety risk in boys during late childhood (at ages 8-10).

Yogi or fireball - or both - a diary study on the interaction between mindfulness and vigor on job performance.

Introduction: Building upon the conservation of resources theory and the episodic process model of performance, this research addresses the gap in understanding how daily variations in two personal resources, particularly their interaction, affect job performance. Specifically, this study examines the influence of vigor and mindfulness on daily fluctuations in task performance considering the potential compensation effect between these personal resources in the workplace. Methods: We conducted a five-day online diary study involving 192 participants (926 daily observations). At the conclusion of each workday, participants were asked to assess their level of mindfulness and vigor in the workplace using validated scales, as well as estimate their task performance. Results: Multilevel analyses showed that both daily mindfulness and daily vigor positively predict self-reported task performance. The interaction between mindfulness and vigor was significant. The results suggest that high levels of mindfulness can compensate for low levels of vigor, and vice versa. Discussion: Exploring the interplay of personal resources at work provides a valuable starting point for individual-tailored interventions that enable individuals to reach their full potential. Enhancing employees' mindfulness may increase job performance directly and empowers workers to compensate for periods of low energy.

The day-level effects of recovery community center attendance on indicators of recovery wellbeing and risk.

BACKGROUND: Recovery community centers (RCCs) are a relatively new resource in the recovery support landscape aimed at building their members' recovery capital. In recent years, interest in the value of RCCs has grown, however, no studies have used within-person methods to consider how RCCs may impact the day-to-day lives of their attendees. Using within-person data drawn from members of RCCs, this study examined how visiting RCCs was associated with several same-day indicators of recovery wellbeing and risk: daily sense of meaningfulness, recovery identity, negative affect, and positive affect. METHODS: Participants were 94 visitors of six RCCs in western Pennsylvania. Daily diary methods collected 10 nightly reports of daily RCC attendance and end-of-day meaningfulness, recovery identity, negative affect, and positive affect. Multilevel modeling accounted for nesting in the intensive longitudinal data. In independent models, the study regressed meaningfulness, recovery identity, negative affect, and positive affect onto day- and person-level RCC attendance. RESULTS: Within-person associations between RCC attendance and meaningfulness (b = 6.96, SE = 1.66, p < .001), recovery identity (b = 4.75, SE = 1.08, p < .001), and PA (b = 3.82, SE = 1.45, p < .01) were significant, although NA was not (b = -2.41, SE = 1.34, n.s.). All day- by person-level RCC attendance interactions (in preliminary models) and between-person associations were non-significant across recovery outcomes. CONCLUSIONS: The results indicated that on days participants visited RCCs, they reported significantly higher levels of meaningfulness, recovery identity, and positive affect, although negative affect levels did not significantly differ. Also, those who attended RCCs more frequently did not generally report different levels of recovery wellbeing and risk. Taken together, results suggest visiting RCCs works on a daily basis to support interpersonal processes related to positive recovery outcomes. That RCC visits do not appear to reduce negative affect suggests that additional programs may be needed to address negative affect. The within-person design provided insight into the dynamic processes that contribute to the intrapersonal states that support recovery and a practical approach to examining whether and how RCCs might support recovery. By using individuals as their own controls, the study design provided strong counterfactual inference.

What ergodicity means for you.

This paper explores the relation between within-person and between-person research designs using the concept of ergodicity from statistical mechanics in physics. We demonstrate the consequences of ergodicity using several real data examples from previously published studies. We then create several simulated examples that illustrate the independence of within-person processes from between-person differences, and pair these examples with analytic results that reinforce our conclusions. Finally, we discuss the plausibility of ergodicity being the general rule rather than the exception for social and behavioral processes, address common arguments against heeding the implications of ergodicity for behavioral research, and offer several possible solutions.

Extended ambulatory assessment of executive function: within-person reliability of working memory and inhibitory control tasks.

INTRODUCTION: Ambulatory assessment of executive function - particularly in the form working memory (WM) - is increasingly common. Few studies to date, however, have also incorporated ambulatory measures of inhibitory control. Critically, the extended within-person reliability of ambulatory tasks tapping each of these constructs has been largely overlooked. METHOD: Participants (N = 283, Mage = 23.74 years, SD = 9.04) received notifications every 3 days (for 4 weeks) to undertake ambulatory assessment versions of the n-Back and Stop-Signal Tasks (SST) via the smartphone application CheckCog. Within-person reliability of these measures was explored. RESULTS: Compliance ranged from 66% (for eight sessions) to 89% (for four sessions). Our results reveal significant changes in performance within the first two sessions for both the n-Back and SST, with performance remaining largely consistent across the remaining (two to eight) sessions. In terms of test-retest reliability, the ICC (C, 1) values ranged from .29 to .68 on the n-Back (with overall accuracy being .51) and .31-.73 on the SST (with stop-signal reaction time being .53). CONCLUSION: The results of the current study contribute to the literature by demonstrating the reliability of brief measures of executive function - in the form of inhibitory control and WM - delivered using smartphones in participants' natural environments. Based on our findings, the CheckCog app reliability tracks baseline systematic changes in WM and response inhibition across multiple time points and for an extended period in healthy individuals.

Do patients internalize the positive regard they are offered? A dyadic test of a Rogerian condition.

OBJECTIVE: Positive regard (PR) reflects a therapist's unconditional prizing of their patient, which meta-analytically correlates positively with patient improvement. However, most research has been limited to single-participant ratings of PR at a specific time, which neglects the dyadic and dynamic nature of PR (i.e., fundamental to benefitting from therapist-offered PR is that a patient internalizes it). Testing this premise, we hypothesized that therapist-offered PR at one session would predict patient-felt PR at a subsequent session (two sessions later), which would in turn predict the patient's next-session outcome (within-patient mediation). METHOD: Eighty-four patients with generalized anxiety disorder received cognitive-behavioral therapy with or without motivational interviewing. Therapists and patients provided postsession ratings of their offered and felt PR, respectively, at odd-numbered sessions throughout treatment. Patients rated their worry following each even-numbered session. We used multilevel structural equation modeling to test our hypothesis. We explored whether treatment condition moderated the mediational path. RESULTS: As predicted, when a therapist regarded their patient more than usual following one session, the patient felt more regarded than usual. In turn, this internalized regard was negatively associated with worry. Treatment condition did not moderate this path. DISCUSSION: Results support internalized positive regard as a treatment-common, ameliorative relationship process.

The ups and downs of self-criticism and disordered eating: Complementing Paranjothy and Wade's (2024) analysis by considering both trait and state perspectives.

Paranjothy and Wade's (2024) meta-review reveals that individuals higher in the personality trait of self-criticism consistently experience more disordered eating than those lower in the trait. The clinical implications of this meta-review are important in that they suggest current theoretical models and clinical practices in the field of eating disorders should incorporate a greater focus on self-criticism. Building on this exciting contribution, we highlight conceptual, practical, and empirical reasons why the field would benefit from supplementing this research on trait self-criticism with investigations of state self-criticism. We review research showing that self-criticism levels vary not only between individuals, with some people chronically more self-critical than others, but also within a person, with a given individual enacting relatively more self-criticism during some moments and days than others. We then present emerging research showing that these periods of higher-than-usual self-criticism are associated with more disordered eating. Thus, we emphasize the need to explore the factors that give rise to self-critical states in daily life, and review preliminary findings on this topic. We highlight the ways in which research on within-person variations in self-criticism can complement research on trait self-criticism to advance case formulation, prevention, and treatment in the field of eating disorders.

Examining dynamic developmental trends: the interrelationship between age-friendly environments and healthy aging in the Chinese population-evidence from China Health and Retirement Longitudinal Study, 2011-2018.

BACKGROUND: The objective of this research is to investigate the dynamic developmental trends between Age-Friendly Environments (AFE) and healthy aging in the Chinese population. METHODS: This study focused on a sample of 11,770 participants from the CHARLS and utilized the ATHLOS Healthy Aging Index to assess the level of healthy aging among the Chinese population. Linear mixed model (LMM) was used to explore the relationship between AFE and healthy aging. Furthermore, a cross-lagged panel model (CLPM) and a random-intercept cross-lagged panel model (RI-CLPM) were used to examine the dynamic developmental trends of healthy aging, taking into account both Between-Person effects and Within-Person effects. RESULTS: The results from LMM showed a positive correlation between AFE and healthy aging (ß = 0.087, p < 0.001). There was a positive interaction between the geographic distribution and AFE (central region * AFE: ß = 0.031, p = 0.038; eastern region * AFE: ß = 0.048, p = 0.003). In CLPM and RI-CLPM, the positive effect of healthy aging on AFE is a type of Between-Person effects (ß ranges from 0.147 to 0.159, p < 0.001), while the positive effect of AFE on healthy aging is Within-Person effects (ß ranges from 0.021 to 0.024, p = 0.004). CONCLUSION: Firstly, individuals with high levels of healthy aging are more inclined to actively participate in the development of appropriate AFE compared to those with low levels of healthy aging. Furthermore, by encouraging and guiding individuals to engage in activities that contribute to building appropriate AFE, can elevate their AFE levels beyond the previous average level, thereby improving their future healthy aging levels. Lastly, addressing vulnerable groups by reducing disparities and meeting their health needs effectively is crucial for fostering healthy aging in these populations.

Idiographic bidirectional associations of stressfulness of events and negative affect in daily life as indicators for mental health: An experience sampling study.

Evidence suggests that complex micro-dynamics occurring in daily life underly the development of mental distress. We aimed to (1) study the cross-lagged association between stressful events and negative affect (NA), (2) show that there is substantial between-person variability in idiographic associations and (3) show that idiographic associations are indicative of mental health. Experience sampling study assessing perceived stressfulness of events (PSE) and NA four times per day for 2 weeks in a non-clinical convenience sample (N = 70, mean age = 22.9, 61% female, 69% German). Bivariate vector autoregressive model implemented in dynamic structural equation modelling to model the associations between stressful events and NA and obtain idiographic associations. Stressfulness of events and NA were significantly reciprocally associated. Autocorrelations and cross-lagged associations from PSE to NA showed substantial variability and were significantly related with trait measures of depression, anxiety, well-being, and perceived stress. Contrary to expectations, cross-lagged associations from NA to stressfulness of events were not related to trait mental health. The approach outlined in this article is useful for studying idiographic dynamics in daily life. The findings increase our understanding of micro-dynamics underlying mental health and individual differences in these processes.