Positive affective functioning in anhedonic individuals' daily life: Anything but flat and blunted

The effect of positive mental imagery versus positive verbal thoughts on anhedonia

Anhedonia, the loss of interest in and pleasure from previously enjoyable activities is a core symptom of depression and presents a major challenge to treatments. Interventions involving positive mental imagery generation have been suggested to reduce anhedonia. However, it is not clear whether the imagery component of such interventions is crucial for these effects. The current study aimed to test this by contrasting repeated generation of positive mental imagery versus positive verbal thoughts. Over a one-week period, 53 mildly anhedonic adults completed five sessions of a computerized training program involving the generation of either positive images or positive sentences. Compared to participants who generated sentences, participants who generated imagery showed greater improvements from pre- to post-training on an individualized multi-facetted measure of anhedonia (the Dimensional Anhedonia Rating Scale), but not on standardized measures of anticipated pleasure (the Snaith-Hamilton Pleasure Scale), depression symptoms, or positive affect. The present study supports the proposal that positive imagery could provide a route to improve anhedonia, with generation of imagery in particular (as opposed to positive thoughts in general) as an important driving mechanism for these effects. This has theoretical and clinical implications for understanding the role of imagery in anhedonia and its treatment.

Neural and immune interactions linking early life stress and anhedonia

Early experiences of stress and adversity are associated with blunted reward sensitivity and altered reward learning. Meanwhile, anhedonia is characterized by impairments in reward processing, including motivation, effort, and pleasure. Early life stress (ELS) and anhedonia share psychological, behavioral, and neurobiological correlates, and the system-level interactions that give rise to anhedonia have yet to be fully appreciated. The proposed framework uses a multilevel, multisystem approach to aid in understanding neural-immune interactions that link ELS and anhedonia. The interactions linking anhedonia and ELS presented here include reduced reward sensitivity, alterations in hypothalamic-pituitary-adrenal (HPA) axis response, elevated inflammatory cytokines or physiological markers of stress, and blunted reward circuitry functioning along the mesocorticolimbic pathway. The clinical implications and areas for future research are also discussed. Ultimately, this research may inform the development of more specific and individualized treatments for anhedonia.

From the COVID-19 lockdown to the new normal: Two-year changes in daily stress and positive event processes

The emergence of the novel COVID-19 disease and the social distancing measures implemented to curb its spread affected most aspects of daily life. Past work suggests that during times of more severe stress, people respond to daily stressors with relatively higher negative affect. However, little is known about how people responded to daily stressors and positive events at different moments in time during the COVID-19 pandemic. Thus, we examined longitudinal changes in daily event-related affect (covariation of daily stressors or positive events with same-day affect) from Spring 2020 (wave 1) to 2022 (wave 2). The sample consisted of 324 adults aged 18-80 (mean = 52 years; 89% women) from the US and Canada who completed weeklong daily diaries at both waves. The results revealed improvements in affective well-being, stressor-related affect (i.e., smaller fluctuations in affect on stressor days vs. nonstressor days), and positive event-related affect (i.e., lower negative affect on days with vs. without positive events). Furthermore, as people gradually resumed their social activities from 2020 to 2022, people reported being exposed to an increased frequency of both stressors and positive events. This study highlights the potential influence of socio-historical phenomena, such as an ongoing pandemic, on the events that people encounter and how they emotionally respond to them.

Health and Well-Being Among College Students in the United States During the COVID-19 Pandemic: Daily Diary Study

BACKGROUND

There is evidence that anxiety and stress increased among college students during the COVID-19 pandemic. However, less is known about daily experiences of affect, worry, substance use behaviors, experiences of pleasure, concern over food security, experiences of bias or discrimination, feelings of belongingness, and other indicators of well-being and how they vary across days in this population.

OBJECTIVE

This study surveyed a wide range of indicators of health and well-being in daily life over 21 days with a sample of college students in a large university system in the United States during the pandemic. The overall variance in each daily measure was partitioned to reflect the proportion due to (1) between-person differences versus (2) within-person, day-to-day variability. This is important because measures that vary primarily due to between-person differences may be more amenable to interventions that target particular students, whereas measures that vary more due to day-to-day variability may be more amenable to interventions that target day-level contextual factors.

METHODS

A sample of 2068 young adult college students (aged 18-24, mean 19.8, SD 1.3 years; 66.6% women) completed a baseline survey; 97.3% (n=2012) then completed up to 21 consecutive daily surveys that assessed a comprehensive set of daily markers of health, behavior, and well-being. The daily diary study produced a total of 33,722 person-days.

RESULTS

Among all person-days, a minority were substance use days (eg, 14.5% of days involved alcohol use, 5.6% vaping, and 5.5% cannabis). Experiences of pleasure were reported on most (73.5%) days. Between-person differences explained more than 50% of the variance in numerous indicators of health and well-being, including daily vaping, cannabis use, other illicit substance use, experiences of bias or discrimination, positive affect, negative affect, worry, food insecurity, and feelings of belonging at the university. In contrast, within-person differences explained more than 50% of the variance in daily alcohol use, cigarette use, stress, experiences of pleasure, where the student slept last night, and physical activity.

CONCLUSIONS

College student health and well-being are multifaceted, with some aspects likely driven by person-level characteristics and experiences and other aspects by more dynamic, contextual risk factors that occur in daily life. These findings implicate services and interventions that should target individual students versus those that should target days on which students are at high risk for poor experiences or behaviors.

Cognitive Signatures of Depressive and Anhedonic Symptoms and Affective States Using Computational Modeling and Neurocognitive Testing

BACKGROUND

Deeper phenotyping may improve our understanding of depression. Because depression is heterogeneous, extracting cognitive signatures associated with severity of depressive symptoms, anhedonia, and affective states is a promising approach.

METHODS

Sequential sampling models decomposed behavior from an adaptive approach-avoidance conflict task into computational parameters quantifying latent cognitive signatures. Fifty unselected participants completed clinical scales and the approach-avoidance conflict task by either approaching or avoiding trials offering monetary rewards and electric shocks.

RESULTS

Decision dynamics were best captured by a sequential sampling model with linear collapsing boundaries varying by net offer values, and with drift rates varying by trial-specific reward and aversion, reflecting net evidence accumulation toward approach or avoidance. Unlike conventional behavioral measures, these computational parameters revealed distinct associations with self-reported symptoms. Specifically, passive avoidance tendencies, indexed by starting point biases, were associated with greater severity of depressive symptoms (R = 0.34, p = .019) and anhedonia (R = 0.49, p = .001). Depressive symptoms were also associated with slower encoding and response execution, indexed by nondecision time (R = 0.37, p = .011). Higher reward sensitivity for offers with negative net values, indexed by drift rates, was linked to more sadness (R = 0.29, p = .042) and lower positive affect (R = -0.33, p = .022). Conversely, higher aversion sensitivity was associated with more tension (R = 0.33, p = .025). Finally, less cautious response patterns, indexed by boundary separation, were linked to more negative affect (R = -0.40, p = .005).

CONCLUSIONS

We demonstrated the utility of multidimensional computational phenotyping, which could be applied to clinical samples to improve characterization and treatment selection.

An integrative analysis of potential mechanisms of reduced positive affect in daily life in depression: an ESM study

Decreased levels of positive affect (PA) are a hallmark of depression. Current models propose as potential main mechanisms a dysfunctional use of emotion regulation (ER) strategies (i.e. dampening, positive rumination), and a maladaptive activation of pro-hedonic goals. However, the role of these mechanisms in PA in daily life remains understudied. We used a 10-day ESM design to assess how these mechanisms influence each other and contribute to depressive symptomatology-related low momentary PA in 139 individuals. Higher depressive symptoms were associated with lower PA, pro-hedonic goals, more frequent use of positive rumination, and higher use of dampening. Further, experiencing higher levels of PA predicted lower following time point use of dampening in individuals with higher symptoms. Finally, using positive rumination was more beneficial (i.e. predicted higher PA increases one moment later) for individuals with higher symptomatology. Our findings suggest that moment-to-moment changes in PA daily life are affected by, and have an effect on, both pro-hedonic goals and the use of dampening and positive rumination, highlighting specific cognitive-affective mechanisms that should be considered when designing interventions aimed at improving low PA characterising depression symptomatology.

Daily Affective Dynamics in Major Depressive Disorder: The Role of Daily Stressors and Positive Events

This study examined daily affective dynamic indices among individuals with a major depressive disorder (MDD) diagnosis in the past one year at the time of the interview, focusing on affective variability and change in affect in response to daily events (affective reactivity). Data were from the main survey and daily diary project of the Midlife in the United States (MIDUS) study. Participants (N = 1,970; nMDD = 202; nnon-MDD = 1,768) completed structured clinical interviews on mental health and telephone interviews about their daily experiences spanning eight consecutive days. Multilevel models revealed that the MDD group experienced greater positive (PA) and negative affect (NA) variability than the non-MDD group. On days that at least one stressful event was reported, the MDD group experienced a greater decrease in PA and a greater increase in NA. On days that at least one positive event was reported, the MDD group experienced a greater increase in PA and a greater decrease in NA. Changes in affect to daily events, particularly the mood brightening effect, may be indicators of depression and potential targets for intervention. Limitations of the study include a community sample, reliance on self-reported measures of daily stressors and positive events, inclusion of remitted and current MDD participants, and the DSM-III-R based criteria for MDD diagnosis.

Testing the mood brightening hypothesis: Hedonic benefits of physical, outdoor, and social activities in people with anxiety, depression or both

BACKGROUND

The mood brightening hypothesis postulates that people with depressive symptoms report more positive affect (PA) and less negative affect (NA) than healthy controls after rewarding daily life activities. Whether mood brightening also occurs in people with anxiety symptoms remains unclear. This study examined effects of physical activity, being outdoors, and social activity on PA and NA across different levels of depression and anxiety symptoms in the general Dutch population.

METHODS

Participants completed an electronic diary on their smartphone, thrice daily over 30 days, to assess activities and affect (n = 430; 22,086 assessments). We compared five groups based on their scores on the Depression, Anxiety and Stress Scales: asymptomatic participants, participants with mild symptoms of depression and/or anxiety, depression symptoms, anxiety symptoms, and comorbid depression and anxiety symptoms. Multilevel linear regression models with interaction terms were used to compare the association between activities and affect in these five groups.

RESULTS

All activities were associated with increased PA and reduced NA in all groups. We found a mood brightening effect in participants with depression, as physical activity and being outdoors were associated with reduced NA. Participants with depression had increased PA and reduced NA when in social company compared to asymptomatic participants. No mood brightening effects were observed in participants with anxiety or comorbid depression and anxiety.

LIMITATIONS

Our sample included mainly women and highly educated subjects, which may limit the generalizability of our findings.

CONCLUSION

Mood brightening is specific to depression, and typically stronger when in social company.

GENETIC AND ENVIRONMENTAL CONTRIBUTIONS TO POSITIVE AFFECT: INSIGHTS FROM ADOLESCENT TWINS

Disturbances in positive affect and reductions in social reward/interpersonal pleasure are common across a range of clinical disorders and are often related. We examined the relationship between the Anticipatory and Consummatory Interpersonal Pleasure Scale (ACIPS-A), and other measures of positive affect in adolescents in a genetically informative research design. The sample consisted of 177 MZ and 136 same sex DZ twins drawn from a study of adolescent twins (M = 16.4 ± .97 years) who were part of the Wisconsin Twin Project. The self-report questionnaires included the Behavioral Activation Scale (BAS), Psychological Well-Being Scale, revised Early Adolescent Temperament Questionnaire (EATQR) and the adolescent version of the ACIPS (ACIPS-A). Structural equation modeling estimated the relative contribution of genetic and environmental factors to the phenotypic variance in each of the measures. Follow-up bivariate analyses parsed the genetic and environmental contributions to the phenotypic covariances between the ACIPS-A and each of the other measures of positive affect. We found evidence of moderate heritability for the ACIPS-A scale scores. Overall, models specifying additive genetic and unique environmental effects (AE models) were the most parsimonious models for each of the measures. Several of the measures showed moderate positive phenotypic intercorrelations, and all but one of these intercorrelations showed significant partial genetic underpinnings. Moreover, the bivariate biometric analyses indicated that the ACIPS-A also captures unique heritable variation. Thus, the ACIPS-A captures unique heritable contributions to social/interpersonal pleasure, as well as shared genetic variance with other measures of positive affectivity.

Elucidating negative symptoms in the daily life of individuals in the early stages of psychosis

BACKGROUND

It remains poorly understood how negative symptoms are experienced in the daily lives of individuals in the early stages of psychosis. We aimed to investigate whether altered affective experience, anhedonia, social anhedonia, and asociality were more pronounced in individuals with an at-risk mental state for psychosis (ARMS) and individuals with first-episode psychosis (FEP) than in controls.

METHODS

We used the experience sampling methodology (ESM) to assess negative symptoms, as they occurred in the daily life of 51 individuals with FEP and 46 ARMS, compared with 53 controls.

RESULTS

Multilevel linear regression analyses showed no overall evidence for a blunting of affective experience. There was some evidence for anhedonia in FEP but not in ARMS, as shown by a smaller increase of positive affect (BΔat-risk v. FEP = 0.08, p = 0.006) as the pleasantness of activities increased. Against our expectations, no evidence was found for greater social anhedonia in any group. FEP were more often alone (57%) than ARMS (38%) and controls (35%) but appraisals of the social situation did not point to asociality.

CONCLUSIONS

Overall, altered affective experience, anhedonia, social anhedonia and asociality seem to play less of a role in the daily life of individuals in the early stages of psychosis than previously assumed. With the experience of affect and pleasure in daily life being largely intact, changing social situations and appraisals thereof should be further investigated to prevent development or deterioration of negative symptoms.

Personality differences in the occurrence and affective correlates of daily positive events

OBJECTIVE

Previous research shows that Neuroticism predicts exposure and affective reactivity to daily stressors. Zautra and colleagues extended this work to daily positive events. Building on these frameworks, we examined the Big Five personality traits as predictors of the occurrence and affective correlates of daily positive events.

METHOD

Participants in two national U.S. daily diary studies (NSDE 2: N = 1,919 and NSDE Refresher: N = 778; aged 25-84) reported daily positive events, emotions specific to the events, and daily affect for 8 consecutive days.

RESULTS

In parallel analyses in both samples, Extraversion and in the NSDE Refresher sample only Openness (but not Neuroticism, Conscientiousness, or Agreeableness) predicted more frequent positive event occurrence. All Big Five traits were associated with one or more emotional experiences (e.g., calm, proud) during positive events. Neuroticism predicted greater event-related positive affect in the NSDE 2 sample, whereas Agreeableness was related to more event-related negative affect in the NSDE Refresher sample.

CONCLUSIONS

The Big Five personality traits each provided unique information for predicting positive events in daily life. The discussion centers on potential explanations and implications for advancing the understanding of individual differences that contribute to engagement in positive experiences.

I feel good? Anhedonia might not mean "without pleasure" for people treated for opioid use disorder

Anhedonia is usually defined as partial or total loss of the capacity for pleasure. People with anhedonia in the context of major depressive disorder may have an unexpected capacity for event-related mood brightening, observable when mood is assessed dynamically (with smartphone-based ecological momentary assessment [EMA]) rather than only statically via questionnaire. We used EMA to monitor mood and pleasant events for 4 weeks in 54 people being treated with opioid agonist medication for opioid-use disorder (OUD), which is also associated with anhedonia, said to manifest especially as loss of pleasure from nondrug reward. We compared OUD patients' EMA reports with those of 47 demographically similar controls. Background positive mood was lower in OUD patients than in controls, as we hypothesized (Cohen ds = .85 to 1.32, 95% CIs [.66, 1.55]), although, contrary to our hypothesis, background negative mood was also lower (ds = .82 to .85, 95% CIs [.73, .94]). As hypothesized, instances of nondrug pleasure were as frequent in OUD patients as in controls-and were not rated much less pleasurable (d = .18, 95% CI [-.03, .35]). Event-related mood brightening occurred in both abstinent and nonabstinent OUD patients (ds = .18 to .37, CIs [-.01, .57]) and controls (ds = .04 to .60, CIs [-.17, .79]), brightening before each event began earlier for controls than OUD patients, but faded similarly postevent across groups. Our findings add to the evidence that anhedonia does not rule out reactive mood brightening, which, for people with OUD being treated on opioid agonist medication, can be elicited by nondrug activities. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

[Positive cognitive neuroscience : Positive valence systems of the Research Domain Criteria initiative]

In diesem Artikel werden die Domäne „positive Valenzsysteme“ (PVS) der Research-Domain-Criteria(RDoC)-Matrix sowie ihre Subkonstrukte dargestellt und erläutert. Unter PVS fallen im Wesentlichen verschiedene Formen und Prozesse der Belohnungsverarbeitung. Diese werden in der Psychiatrie schon seit Jahrzehnten im Bereich von Sucht, Schizophrenie und Depression untersucht und letztere sind daher nicht Gegenstand dieses Artikels. Hier soll vielmehr die heuristische Fruchtbarkeit der RDoC-Systematik für das Verständnis anderer Erkrankungen und Konstrukte dargestellt werden und zwar für das transdiagnostische Konstrukt der Anhedonie sowie für die Autismusspektrumstörung und die Gruppe der Essstörungen. Weiterhin wird gezeigt, wie die PVS-Domäne auch klinisch den Blick über die traditionelle Psychopathologie erweitert und wie sie die Entwicklung neuer behavioraler Messinstrumente angeregt hat. Abschließend wird auf Limitationen und mögliche zukünftige Erweiterungen des Ansatzes eingegangen.

Anhedonia, positive affect dysregulation, and risk and maintenance of binge-eating disorder

Low positive affect has been identified as an antecedent of binge-eating episodes among individuals with binge-eating disorder (BED), yet positive affect has received far less attention in eating disorders research than its counterpart, negative affect. In this article, we argue that the low levels of positive affect which occur with anhedonia (i.e., loss of interest or pleasure in activities) may contribute to the onset and maintenance of BED. We introduce a theoretical model in which anhedonia increases the risk for BED through its interrelationships with dysregulated eating and weight gain, and we describe potential direct (e.g., reward-related processes) as well as indirect (e.g., influences on depressive symptoms and physical activity) pathways by which anhedonia may lead to adverse eating- and weight-related outcomes. We also propose a momentary maintenance model in which low positive affect and positive affect dysregulation occurring with anhedonia maintain binge eating directly and indirectly through maladaptive health behaviors, such as decreased physical activity, less healthy eating, and fewer social interactions, which in turn maintain anhedonia. We draw upon outside literature to present evidence that aligns with the proposed risk and maintenance models and conclude by outlining avenues for future research-including methodological/measurement, theoretical, and clinical research directions.

Increased Reward-Related Activation in the Ventral Striatum During Stress Exposure Associated With Positive Affect in the Daily Life of Young Adults With a Family History of Depression. Preliminary Findings

Background: Being the offspring of a parent with major depression disorder (MDD) is a strong predictor for developing MDD. Blunted striatal responses to reward were identified in individuals with MDD and in asymptomatic individuals with family history of depression (FHD). Stress is a major etiological factor for MDD and was also reported to reduce the striatal responses to reward. The stress-reward interactions in FHD individuals has not been explored yet. Extending neuroimaging results into daily-life experience, self-reported ambulatory measures of positive affect (PA) were shown to be associated with striatal activation during reward processing. A reduction of self-reported PA in daily life is consistently reported in individuals with current MDD. Here, we aimed to test (1) whether increased family risk of depression is associated with blunted neural and self-reported reward responses. (2) the stress-reward interactions at the neural level. We expected a stronger reduction of reward-related striatal activation under stress in FHD individuals compared to HC. (3) the associations between fMRI and daily life self-reported data on reward and stress experiences, with a specific interest in the striatum as a crucial region for reward processing. Method: Participants were 16 asymptomatic young adults with FHD and 16 controls (HC). They performed the Fribourg Reward Task with and without stress induction, using event-related fMRI. We conducted whole-brain analyses comparing the two groups for the main effect of reward (rewarded > not-rewarded) during reward feedback in control (no-stress) and stress conditions. Beta weights extracted from significant activation in this contrast were correlated with self-reported PA and negative affect (NA) assessed over 1 week. Results: Under stress induction, the reward-related activation in the ventral striatum (VS) was higher in the FHD group than in the HC group. Unexpectedly, we did not find significant group differences in the self-reported daily life PA measures. During stress induction, VS reward-related activation correlated positively with PA in both groups and negatively with NA in the HC group. Conclusion: As expected, our results indicate that increased family risk of depression was associated with specific striatum reactivity to reward in a stress condition, and support previous findings that ventral striatal reward-related response is associated with PA. A new unexpected finding is the negative association between NA and reward-related ventral striatal activation in the HC group.

Difficulty envisioning a positive future: Secondary analyses in patients in intensive care who are communication vulnerable

The purpose of this study was to report a secondary analysis of data collected through a primary study. The primary study was a, randomized, control trial that used a team-designed (nursing, speech language hearing, engineering, communication sciences, and biostatistics), nurse-led, electronic communication intervention (Speak for Myself Voice) and measured patient outcomes of symptoms of anxiety and depression in five intensive care units at a regional, magnet-status, academic medical center. A secondary analysis of data using the Hospital Anxiety and Depression scale is reported here. The extant literature supports patient expressions of frustration, anger, anxiety, and depression when unable to communicate. This secondary analysis study report adds information about Hospital Anxiety and Depression subscales in the communication-vulnerable population. Implications include emerging awareness of potential feelings of depression and anxiety in patients who are receiving mechanical ventilation or who are unable to verbally communicate for any reason (e.g. obstruction, trauma, head and neck cancer) in the intensive care unit.

Diminished Anticipatory and Consummatory Pleasure in Dysphoria: Evidence From an Experience Sampling Study

Anhedonia, the experience of diminished pleasure, is a core feature of major depressive disorder and is often present long before the diagnosis of depression. Most previous studies have investigated anhedonia with self-report measures of trait anhedonia or with behavioral paradigms using laboratory stimuli, and the real-time characteristics of hedonic processing in subclinical depression remain under-investigated. We used the experience sampling method to evaluate momentary experience of hedonic feelings in the context of daily life. Dysphoric (n = 49) and non-dysphoric (n = 51) college students completed assessments of their current positive affect (PA), as well as state anticipatory and consummatory pleasure, 3 or 4 times a day every day for 2 weeks. The results showed that dysphoric individuals reported less state anticipatory and consummatory pleasure compared with non-dysphoric individuals. Moreover, significant time-lagged associations between anticipatory pleasure and follow-up consummatory pleasure were found in the whole sample, after adjustment for current PA. The current findings thus hold considerable promise in advancing our understanding of anhedonia as well as the important role of state anticipatory pleasure in relation to depression.

Humour processing deficits in individuals with social anhedonia

Humour processing comprises the humour comprehension and the humour appreciation phases. Patients with schizophrenia have impaired humour processing. However, it is unclear whether such deficits affect subclinical populations such as individuals with social anhedonia. Our study recruited forty-eight individuals with high levels of social anhedonia (HSA, screened by the Revised Chapman Social Anhedonia Scale) and 50 individuals with low levels of social anhedonia (LSA). Participants completed behavioural tasks which tapped into humour comprehension and appreciation, and a set of questionnaires assessing their sense of humour, humour styles and subjective experiential pleasure. Using signal detection theory analysis, the d' and β values were generated to measure the detection of humour signal in the comprehension phase and the inner criteria of the humour appreciation respectively. The results showed that the HSA and LSA groups did not differ in humour signal detection (d') but the HSA group had significantly higher inner criteria of humour appreciation (β) than the LSA group. The β value was correlated with experiential anticipatory pleasure in all participants. The HSA group had significantly lower within-group coherence than the LSA group when processing humour. Our findings suggested that individuals with social anhedonia have impaired humour processing.

Daily Affect and Self-Esteem in Early Adolescence: Correlates of Mean Levels and Within-Person Variability

Emotions and self-esteem are critical components of well-being and adaptation during adolescence. People differ in their average levels of affect and self-esteem, as well as in how much their affect and self-esteem fluctuate from moment to moment. Fluctuations in affect in particular have not been extensively examined in relation to adolescent-relevant variables. The present study investigates internalizing symptoms, social functioning, and overt and relational aggression as correlates of average levels and within-person variability in daily positive and negative affect (PA and NA) and self-esteem. Crucially, unique association were examined controlling for the other variables. Early adolescents (mean age 10.8 years, N = 94) completed daily diaries across four days on PA, NA, and self-esteem. They also completed general questionnaires, as did peers. Some key findings were that more internalizing symptoms were significantly associated with more variability in NA. The importance of peer relationships for adolescents' daily mean levels of PA and NA were shown. Peer-perceived social functioning was associated with less fluctuations in self-esteem. Some unexpected, non-significant, findings for aggression appeared. Finally, higher mean NA were associated with more NA fluctuations, whereas higher mean PA and self-esteem were associated with less fluctuations.

The dynamical signature of anhedonia in major depressive disorder: positive emotion dynamics, reactivity, and recovery

BACKGROUND

Major Depressive Disorder (MDD) is the leading cause of disability worldwide. The cardinal features of MDD are depressed mood and anhedonia. Anhedonia is defined as a "markedly diminished interest or pleasure in all, or almost all, activities of the day", and has generally been investigated on group-level using retrospective data (e.g. via questionnaire/interview). However, inferences based on group-level findings not necessarily generalize to daily life experiences within individuals.

METHODS

We repeatedly sampled pleasurable experiences within individuals' daily lives by means of Experience Sampling Methods, and compared how positive affect unfolded in the daily life of healthy controls versus patients diagnosed with MDD and anhedonia. We sampled Positive Affect (PA) and reward experiences on 10 semi-random time points a day, for seven days in the daily lives of 47 MDD patients with anhedonia, and 40 controls.

RESULTS

Multilevel models showed that anhedonia was associated with low PA, but not to differences in PA dynamics, nor reward frequency in daily life. In reaction to rewards, MDD patients with anhedonia showed no difference in their increase in PA (i.e., PA reactivity), and showed no signs of a faster return to baseline thereafter (i.e., PA recovery).

CONCLUSIONS

Our results suggest that the dynamical signature of anhedonia in MDD can be described best as a lower average level of PA, and "normal" in terms of PA dynamics, daily reward reactivity and reward recovery. Preregistration: https://osf.io/gmfsc/register/565fb3678c5e4a66b5582f67 . Preprint: https://osf.io/cfkts.

Experience sampling methodology in mental health research: new insights and technical developments

In the mental health field, there is a growing awareness that the study of psychiatric symptoms in the context of everyday life, using experience sampling methodology (ESM), may provide a powerful and necessary addition to more conventional research approaches. ESM, a structured self-report diary technique, allows the investigation of experiences within, and in interaction with, the real-world context. This paper provides an overview of how zooming in on the micro-level of experience and behaviour using ESM adds new insights and additional perspectives to standard approaches. More specifically, it discusses how ESM: a) contributes to a deeper understanding of psychopathological phenomena, b) allows to capture variability over time, c) aids in identifying internal and situational determinants of variability in symptomatology, and d) enables a thorough investigation of the interaction between the person and his/her environment and of real-life social interactions. Next to improving assessment of psychopathology and its underlying mechanisms, ESM contributes to advancing and changing clinical practice by allowing a more fine-grained evaluation of treatment effects as well as by providing the opportunity for extending treatment beyond the clinical setting into real life with the development of ecological momentary interventions. Furthermore, this paper provides an overview of the technical details of setting up an ESM study in terms of design, questionnaire development and statistical approaches. Overall, although a number of considerations and challenges remain, ESM offers one of the best opportunities for personalized medicine in psychiatry, from both a research and a clinical perspective.