[Ecological momentary assessment as a clinical tool in psychiatry: promises, pitfalls, and possibilities]. / Dagboekmetingen als hulpmiddel in de psychiatrische zorg: beloften, valkuilen en mogelijkheden.

BACKGROUND: Ecological momentary assessment (EMA) is a promising method to gain insight into the daily lives of people with mental disorders. EMA can be used to monitor mood, symptoms, and experiences multiple times per day. Using advanced statistical methods, such as network analysis, as EMA feedback might result in novel insights that are relevant to psychiatric care. AIM: To investigate the promise, pitfalls, and possibilities of EMA and network analysis for psychiatric care. METHOD: Empirical network studies, reviews, and qualitative research were employed to investigate the state of research and the perspectives of patients and clinicians on EMA and network analysis. Furthermore, an empirical study will be discussed, in which twenty patients with bipolar disorders completed five EMA diaries per day for four months within treatment. RESULTS: Studies using network analysis demonstrated conflicting results. Qualitative research indicated that bipolar patients and clinicians are aware of the added benefit of EMA for psychiatric care, especially for improving insight and self-management. At the same time, EMA was seen as burdensome. Personalization and integration with existing treatment protocols emerged as necessary requirements for adequate implementation of EMA in psychiatric care. CONCLUSION: EMA can have added value for psychiatric care, provided it is adequately implemented. BACKGROUND: Ecological momentary assessment (EMA) is a promising method to gain insight into the daily lives of people with mental disorders. EMA can be used to monitor mood, symptoms, and experiences multiple times per day. Using advanced statistical methods, such as network analysis, as EMA feedback might result in novel insights that are relevant to psychiatric care. AIM: To investigate the promise, pitfalls, and possibilities of EMA and network analysis for psychiatric care. METHOD: Empirical network studies, reviews, and qualitative research were employed to investigate the state of research and the perspectives of patients and clinicians on EMA and network analysis. Furthermore, an empirical study will be discussed, in which twenty patients with bipolar disorders completed five EMA diaries per day for four months within treatment. RESULTS: Studies using network analysis demonstrated conflicting results. Qualitative research indicated that bipolar patients and clinicians are aware of the added benefit of EMA for psychiatric care, especially for improving insight and self-management. At the same time, EMA was seen as burdensome. Personalization and integration with existing treatment protocols emerged as necessary requirements for adequate implementation of EMA in psychiatric care. CONCLUSION: EMA can have added value for psychiatric care, provided it is adequately implemented.

[Antithrombotics: backgrounds with haemostasis and antithrombotic therapy]. / Antitrombotica: achtergronden bij stolling en antistolling.

The clinical guidelines on antithrombotics, published by the Dutch Institute of Expertise for Oral Healthcare, give advice on policy to be followed in cases of dental procedures involving bleeding. The guidelines allow room for professional assessment of bleeding risks, for which background knowledge about haemostasis, thrombosis and antithrombotic processes is necessary. Normal haemostasis can be divided in several steps: vasoconstriction, primary haemostasis by aggregation of thrombocytes, and secondary haemostasis by the formation of fibrin out of coagulation factors. In the case of thrombosis, a blood clot forms inside a blood vessel, causing obstruction of blood flow to the underlying tissue. Various antithrombotics are prescribed for the prevention and treatment of thrombosis. Thrombocyte aggregation inhibitors only have an effect on primary haemostasis. Vitamin K antagonists influence secondary haemostasis by lowering the production of several coagulation factors. The direct oral anticoagulants have an immediate effect on an activated coagulation factor, and are currently prescribed in large quantities [in the Netherlands]. Low-molecular-weight heparin also inhibits activated coagulation factors, but is not used for long-term antithrombotic therapy since it is administrated subcutaneously.

[Using the new clinical guidelines on antithrombotics in the dental practice]. / Toepassen van nieuwe richtlijn 'Antitrombotica' in de mondzorgpraktijk.

A 64-year-old man has deep caries in tooth 37 without acute pain; extraction is indicated, however. According to his list of medications, he takes the antithrombotics apixaban and clopidogrel. Or: a 78-year-old woman has upper and lower dentures that don't function well, and she experiences retention problems. Implant-bearing upper and lower dentures on 4 and 2 implants, respectively, are indicated. The patient takes acenocoumarol and reports that the clotting time value of her blood (INR) sometimes fluctuates. The clinical guidelines 'Dental procedures in patients using antithrombotic medication', which recently appeared, offer oral healthcare providers recommendations for reducing the risk of bleeding while observing the risk of thrombosis. These guidelines by the Dutch Institute of Expertise for Oral Healthcare replace the previous guidelines from 2012. The recommendations are up to date with current practice in the Netherlands and take into account all antithrombotics patients may currently use in an outpatient setting. Furthermore, the responsibilities of the oral healthcare providers and the agreements with thrombosis services are formalised in these guidelines.

More precise dosing of acenocoumarol for better control in patients aged above 80 years, a randomised controlled pilot study.

INTRODUCTION: Many elderly patients are confined to treatment with vitamin K antagonists (VKA) instead of direct oral anticoagulants (DOACs). However, quality of VKA treatment declines with age. This might be caused by the lower dose requirements with increasing age, which result in relatively large day-by-day VKA dose differences. Therefore, more precise dosing with smaller dose increments might improve quality of VKA treatment in the elderly. METHODS: We randomised 80 elderly patients (≥80 years, using 0.5-2 mg acenocoumarol daily) to either conventional dosing with 1.0 mg acenocoumarol increments, or more precise dosing with 0.5 mg increments, to assess effect sizes and feasibility of a larger trial. We compared changes in the time in therapeutic range (TTR), INR variability and anticoagulation-related quality of life (measured with the PACT-Q) between treatment groups. RESULTS: Overall, baseline TTR was 61.3 ± 19.2. After six study months, TTR had improved to 69.5 ± 19.7 in the precise dosing group versus 67.7 ± 21.2 in the conventional dosing group (absolute difference 3.4 (95% CI -6.7 to 13.6)). The between-groups difference in INR variability was not assessed because of baseline differences. PACT-Q convenience declined slightly with more precise dosing, compared with conventional dosing: 2.1/100 (95% CI 0.5-3.7). Satisfaction decreased equally in both groups with -6.4 ± 8.6/100. Four dosing errors occurred: three with precise and one with conventional dosing. CONCLUSION: Although more precise dosing of acenocoumarol leads to a slightly higher TTR, this effect is too small to convey a relevant clinical benefit and could be abolished by the increased risk of medication errors.

Polygenic liability for schizophrenia and childhood adversity influences daily-life emotion dysregulation and psychosis proneness.

OBJECTIVE: To test whether polygenic risk score for schizophrenia (PRS-S) interacts with childhood adversity and daily-life stressors to influence momentary mental state domains (negative affect, positive affect, and subtle psychosis expression) and stress-sensitivity measures. METHODS: The data were retrieved from a general population twin cohort including 593 adolescents and young adults. Childhood adversity was assessed using the Childhood Trauma Questionnaire. Daily-life stressors and momentary mental state domains were measured using ecological momentary assessment. PRS-S was trained on the latest Psychiatric Genetics Consortium schizophrenia meta-analysis. The analyses were conducted using multilevel mixed-effects tobit regression models. RESULTS: Both childhood adversity and daily-life stressors were associated with increased negative affect, decreased positive affect, and increased subtle psychosis expression, while PRS-S was only associated with increased positive affect. No gene-environment correlation was detected. There is novel evidence for interaction effects between PRS-S and childhood adversity to influence momentary mental states [negative affect (b = 0.07, P = 0.013), positive affect (b = -0.05, P = 0.043), and subtle psychosis expression (b = 0.11, P = 0.007)] and stress-sensitivity measures. CONCLUSION: Exposure to childhood adversities, particularly in individuals with high PRS-S, is pleiotropically associated with emotion dysregulation and psychosis proneness.

Exploring the emotional dynamics of subclinically depressed individuals with and without anhedonia: An experience sampling study.

BACKGROUND: Anhedonia has been linked to worse prognosis of depression. The present study aimed to construct personalized models to elucidate the emotional dynamics of subclinically depressed individuals with versus without symptoms of anhedonia. METHODS: Matched subclinically depressed individuals with and without symptoms of anhedonia (N = 40) of the HowNutsAreTheDutch sample completed three experience sampling methodology assessments per day for 30 days. For each individual, the impact of physical activity, stress experience, and high/low arousal PA/NA on each other was estimated through automated impulse response function analysis (IRF). These individual IRF associations were combined to compare anhedonic versus non-anhedonic individuals. RESULTS: Physical activity had low impact on affect in both groups. In non-anhedonic individuals, stress experience increased NA and decreased PA and physical activity more strongly. In anhedonic individuals, PA high arousal showed a diminished favorable impact on affect (increasing NA/stress experience, decreasing PA/physical activity). Finally, large heterogeneity in the personalized models of emotional dynamics were found. LIMITATIONS: Stress experience was measured indirectly by assessing level of distress; the timeframe in between measurements was relatively long with 6h; and only information on one of the two hallmarks of anhedonia, loss of interest, was gathered. CONCLUSIONS: Our results suggest different pathways of emotional dynamics underlie depressive symptomatology. Subclinically depressed individuals with anhedonic complaints are more strongly characterized by diminished favorable impact of PA high arousal and heightened NA reactivity, whereas subclinically depressed individuals without these anhedonic complaints seem more characterized by heightened stress reactivity. The automatically generated personalized models may offer patient-specific insights in emotional dynamics, which may show clinical relevance.

Is sensitivity to daily stress predictive of onset or persistence of psychopathology?

PURPOSE: The aim of the current study was to replicate findings in adults indicating that higher sensitivity to stressful events is predictive of both onset and persistence of psychopathological symptoms in a sample of adolescents and young adults. In addition, we tested the hypothesis that sensitivity to mild stressors in particular is predictive of the developmental course of psychopathology. METHODS: We analyzed experience sampling and questionnaire data collected at baseline and one-year follow-up of 445 adolescent and young adult twins and non-twin siblings (age range: 15-34). Linear multilevel regression was used for the replication analyses. To test if affective sensitivity to mild stressors in particular was associated with follow-up symptoms, we used a categorical approach adding variables on affective sensitivity to mild, moderate and severe daily stressors to the model. RESULTS: Linear analyses showed that emotional stress reactivity was not associated with onset (ß=.02; P=.56) or persistence (ß=-.01; P=.78) of symptoms. There was a significant effect of baseline symptom score (ß=.53; P<.001) and average negative affect (NA: ß=.19; P<.001) on follow-up symptoms. Using the categorical approach, we found that affective sensitivity to mild (ß=.25; P<.001), but not moderate (ß=-.03; P=.65) or severe (ß=-.06; P=.42), stressors was associated with symptom persistence one year later. DISCUSSION: We were unable to replicate previous findings relating stress sensitivity linearly to symptom onset or persistence in a younger sample. Whereas sensitivity to more severe stressors may reflect adaptive coping, high sensitivity to the mildest of daily stressors may indicate an increased risk for psychopathology.

Dimensional and discrete variations on the psychosis continuum in a Dutch crowd-sourcing population sample.

BACKGROUND: Mild psychotic experiences are common in the general population. Although transient and benign in most cases, these experiences are predictive of later mental health problems for a significant minority. The goal of the present study was to perform examinations of the dimensional and discrete variations in individuals' reporting of subclinical positive and negative psychotic experiences in a unique Dutch internet-based sample from the general population. METHODS: Positive and negative subclinical psychotic experiences were measured with the Community Assessment of Psychic Experiences in 2870 individuals. First, the prevalence of these experiences and their associations with demographics, affect, psychopathology and quality of life were investigated. Next, latent class analysis was used to identify data-driven subgroups with different symptom patterns, which were subsequently compared on aforementioned variables. RESULTS: Subclinical psychotic experiences were commonly reported. Both positive and negative psychotic experiences were associated with younger age, more negative affect, anxiety and depression as well as less positive affect and poorer quality of life. Seven latent classes ('Low psychotic experiences', 'Lethargic', 'Blunted', 'Distressed', 'Paranormal', 'Distressed/grandiose' and 'Distressed/positive psychotic experiences') were identified that demonstrated both dimensional differences in the number/severity of psychotic experiences and discrete differences in the patterns of reported experiences. CONCLUSION: Subclinical psychotic experiences show both dimensional severity variations and discrete symptom-pattern variations across individuals. To understand and capture all interindividual variations in subclinical psychotic experiences, their number, nature and context (co-occurrence patterns) should be considered at the same time. Only some psychotic experiences may lay on a true psychopathological psychosis continuum.

[Asthma/COPD service in general practice. Study into feasibility and effectiveness]. / Een astma/COPD-dienst voor de huisartsenpraktijk.

OBJECTIVE: A study of the effectiveness and functioning of an asthma/COPD service (AC service). DESIGN: Observational study. METHOD: General practitioners (GPs) in the northern part of the Netherlands can refer patients with airway symptoms to the AC service, which was set up in 2007 by local pulmonologists, GPs and the primary care laboratory CERTE. Before the assessment, patients fill in three questionnaires at home: the Clinical COPD Questionnaire (CCQ), the Asthma Control Questionnaire (ACQ) and a medical history list. The laboratory assesses lung function and a physical examination is carried out. All data is sent via the Internet to a pulmonologist, who advises the GP on diagnosis and treatment via an information system. The pulmonologist can offer a follow-up service if required. For this publication we had access to data from 14,748 registered patients and 3721 follow-up consultations. RESULTS: The pulmonologist diagnosed 6201 (42%) patients with asthma, 2728 (19%) with COPD and 1039 (7%) with 'asthma/COPD overlap syndrome'. The pulmonologist advised that 940 patients (6%) should have a change in medication and reassessment after 3 months. In this group, the number of unstable COPD patients (CCQ ≥ 1) dropped from 134 (67%) to 99 (50%). The number of patients with unstable asthma (ACQ ≥ 1.5) dropped from 245 (3%) to 137 (24%). For 1642 (11%) patients the pulmonologist advised no change in medication and the GP referred the patient for reassessment after 12 months. These patients were generally stable, with a slight improvement in smoking status, exacerbations and inhalation technique. CONCLUSION: Approximately 60% of all patients with asthma or COPD in this region were assessed by the AC service at least once in the period 2007-2014. Advice on diagnosis and treatment given to the GP resulted in better patient-related outcomes in both asthma and COPD patients.

Effects of momentary self-monitoring on empowerment in a randomized controlled trial in patients with depression.

BACKGROUND: Interventions based on the experience sampling method (ESM) are ideally suited to provide insight into personal, contextualized affective patterns in the flow of daily life. Recently, we showed that an ESM-intervention focusing on positive affect was associated with a decrease in symptoms in patients with depression. The aim of the present study was to examine whether ESM-intervention increased patient empowerment. METHODS: Depressed out-patients (n=102) receiving psychopharmacological treatment who had participated in a randomized controlled trial with three arms: (i) an experimental group receiving six weeks of ESM self-monitoring combined with weekly feedback sessions, (ii) a pseudo-experimental group participating in six weeks of ESM self-monitoring without feedback, and (iii) a control group (treatment as usual only). Patients were recruited in the Netherlands between January 2010 and February 2012. Self-report empowerment scores were obtained pre- and post-intervention. RESULTS: There was an effect of group×assessment period, indicating that the experimental (B=7.26, P=0.061, d=0.44, statistically imprecise) and pseudo-experimental group (B=11.19, P=0.003, d=0.76) increased more in reported empowerment compared to the control group. In the pseudo-experimental group, 29% of the participants showed a statistically reliable increase in empowerment score and 0% reliable decrease compared to 17% reliable increase and 21% reliable decrease in the control group. The experimental group showed 19% reliable increase and 4% reliable decrease. CONCLUSIONS: These findings tentatively suggest that self-monitoring to complement standard antidepressant treatment may increase patients' feelings of empowerment. Further research is necessary to investigate long-term empowering effects of self-monitoring in combination with person-tailored feedback.

Daily life stress reactivity in remitted versus non-remitted depressed individuals.

BACKGROUND: Little is known about how daily life mood reactivity to minor stressors (stress reactivity) might change following major depressive disorder (MDD) treatment. We investigate whether (i) mood states and appraisals of daily stressors change after treatment; (ii) stress reactivity to event, activity, or social stress differs; (iii) stress reactivity depends on severity of residual depressive symptoms; and (iv) stress reactivity in individuals with remitted or non-remitted depression differ from that of never-depressed individuals. METHODS: Thirty depressed individuals participated in an experience sampling study before and after a treatment period of 18 months; 39 healthy individuals formed a comparison group. Reactivity of positive affect (PA) and negative affect (NA) to daily stressors were measured. RESULTS: More residual symptoms were associated with larger NA responses to stress. Compared to healthy controls, participants with non-remitted MDD showed higher NA-reactivity to all stressors. In contrast, stress reactivity to event and activity stressors was normalized in remitted patients. However, they still showed heightened NA-reactivity to social stress. CONCLUSIONS: Greater stress reactivity to event and activity stress appears to be state-dependent. The heightened social stress reactivity in remitted patients suggests that sensitivity to social stress may reflect an underlying vulnerability in MDD.

Exploring the underlying structure of mental disorders: cross-diagnostic differences and similarities from a network perspective using both a top-down and a bottom-up approach.

BACKGROUND: It has been suggested that the structure of psychopathology is best described as a complex network of components that interact in dynamic ways. The goal of the present paper was to examine the concept of psychopathology from a network perspective, combining complementary top-down and bottom-up approaches using momentary assessment techniques. METHOD: A pooled Experience Sampling Method (ESM) dataset of three groups (individuals with a diagnosis of depression, psychotic disorder or no diagnosis) was used (pooled N = 599). The top-down approach explored the network structure of mental states across different diagnostic categories. For this purpose, networks of five momentary mental states ('cheerful', 'content', 'down', 'insecure' and 'suspicious') were compared between the three groups. The complementary bottom-up approach used principal component analysis to explore whether empirically derived network structures yield meaningful higher order clusters. RESULTS: Individuals with a clinical diagnosis had more strongly connected moment-to-moment network structures, especially the depressed group. This group also showed more interconnections specifically between positive and negative mental states than the psychotic group. In the bottom-up approach, all possible connections between mental states were clustered into seven main components that together captured the main characteristics of the network dynamics. CONCLUSIONS: Our combination of (i) comparing network structure of mental states across three diagnostically different groups and (ii) searching for trans-diagnostic network components across all pooled individuals showed that these two approaches yield different, complementary perspectives in the field of psychopathology. The network paradigm therefore may be useful to map transdiagnostic processes.

Therapygenetics in mindfulness-based cognitive therapy: do genes have an impact on therapy-induced change in real-life positive affective experiences?

Positive affect (PA) has an important role in resilience against depression and has been shown to increase with mindfulness-based cognitive therapy (MBCT). To elucidate the underlying mechanisms of change in PA as well as develop insights that may benefit personalized medicine, the current study examined the contribution of genetic variation to individual differences in change in PA in response to MBCT. Individuals (n=126) with residual depressive symptoms were randomized to either an MBCT group or treatment as usual. PA was assessed using experience sampling methodology (ESM). Single-nucleotide polymorphisms (SNPs) in genes known to be involved in reward functioning were selected. SNPs in the genes for brain-derived neurotrophic factor (BDNF), the muscarinic acetylcholine receptor M2 (CHRM2), the dopamine receptor D4 (DRD4) and the µ1 opioid receptor (OPRM1) significantly moderated the impact of treatment condition over time on PA. Genetic variation in the genes for CHRM2 and OPRM1 specifically had an impact on the level of PA following MBCT. The current study shows that variation in response to MBCT may be contingent on genetic factors associated with the regulation of PA. These findings contribute to our understanding of the processes moderating response to treatment and prediction of treatment outcome.

Positive emotions from social company in women with persisting subclinical psychosis: lessons from daily life.

OBJECTIVE: Altered social reward functioning is associated with psychosis irrespective of stage and severity. Examining the role of social reward functioning prospectively in relation to psychotic experiences before these become persistent and potentially disabling can aid in elucidating social mechanisms that induce shifts toward more severe psychotic states, without the confounding effects of clinical disorder. METHOD: In a longitudinal general population sample (N = 566), the experience sampling method (repetitive random sampling of momentary emotions and social context) was used to assess daily life social functioning at baseline. Persistence of subclinical psychotic experiences was based on the Community Assessment of Psychic Experiences assessed three times over 14 months. Analyses examined to what degree i) social context and ii) appreciation thereof differentiated between those who did and did not develop persistent psychotic experiences. RESULTS: Although individuals with persistent psychotic experiences did not differ in overall level of positive effect, the amount of time spent alone or the level of social satisfaction compared to individuals without persistent psychotic experiences, they were more sensitive to the rewarding effects of social company. CONCLUSION: Alterations in social reward experience may form one of the mechanisms that precede the development of the extended psychosis phenotype over time.

The dynamic nature of depression: a new micro-level perspective of mental disorder that meets current challenges.

The examination of moment-to-moment, 'micro-level' patterns of experience and behaviour using experience sampling methodology has contributed to our understanding of the 'macro-level' development of full-blown symptoms and disorders. This paper argues that the micro-level perspective can be used to identify the smallest building blocks underlying the onset and course of mental ill-health. Psychopathology may be the result of the continuous dynamic interplay between micro-level moment-to-moment experiences and behavioural patterns over time. Reinforcing loops between momentary states may alter the course of mental health towards either a more or less healthy state. An example with observed data, from a population of individuals with depressive symptoms, supports the validity of a dynamic network model of psychopathology and shows that together and over time, this continuous interplay between momentary states may result in the cluster of symptoms we call major depressive disorder. This approach may help conceptualize the nature of mental disorders, and generate individualized insights useful for diagnosis and treatment in psychiatry.

Novel directions for psychiatric diagnosis: from psychopathology to motor function to monitoring technology.

In the light of the recent publication of the DSM-5, there is renewed debate about the relative merit of categorical diagnosis, as laid down in Diagnostic and Statistical Manual of Mental Disorders (DSM) and International Classification of Diseases (ICD) diagnostic manuals. Issues such as validity, usefulness and acceptability of the diagnoses in this manual are increasingly debated. Several alternative possibilities have been suggested including: (i) the introduction of truly cross-cutting dimensional measures, that would facilitate dynamic multidimensional formulations of psychopathology, (ii) the Research Domain Criteria, that may facilitate biological research but move away from clinical symptoms, (iii) a system of personalized diagnosis based on psychopathology as a network of symptoms and contexts, and (iv) enhanced focus on motor alterations, other than catatonia, as a possible additional informative dimension of diagnosis in psychiatry, particularly as a possible marker of underlying neurodevelopmental alterations. We suggest that novel systems of diagnosis are likely to rely more on continuous monitoring of diagnostically relevant information in daily life, complementing retrospective symptom criteria in DSM and ICD. Patients and their families are likely to benefit from these projects, as novel models of diagnosis based on daily life information may be linked more strongly to treatment needs and prognosis.

Resilience in mental health: linking psychological and neurobiological perspectives.

OBJECTIVE: To review the literature on psychological and biological findings on resilience (i.e. the successful adaptation and swift recovery after experiencing life adversities) at the level of the individual, and to integrate findings from animal and human studies. METHOD: Electronic and manual literature search of MEDLINE, EMBASE and PSYCHINFO, using a range of search terms around biological and psychological factors influencing resilience as observed in human and experimental animal studies, complemented by review articles and cross-references. RESULTS: The term resilience is used in the literature for different phenomena ranging from prevention of mental health disturbance to successful adaptation and swift recovery after experiencing life adversities, and may also include post-traumatic psychological growth. Secure attachment, experiencing positive emotions and having a purpose in life are three important psychological building blocks of resilience. Overlap between psychological and biological findings on resilience in the literature is most apparent for the topic of stress sensitivity, although recent results suggest a crucial role for reward experience in resilience. CONCLUSION: Improving the understanding of the links between genetic endowment, environmental impact and gene-environment interactions with developmental psychology and biology is crucial for elucidating the neurobiological and psychological underpinnings of resilience.

Genetic innovation and stability in externalizing problem behavior across development: a multi-informant twin study.

The use of cross-informant ratings in previous longitudinal studies on externalizing behavior may have obscured the presence of continuity of genetic risk. The current study included latent factors representing the latent estimates of externalizing behavior based on both parent and self-report which eliminated rater-specific effects from these latent estimates. Symptoms of externalizing behavior of 1,480 Swedish twin pairs were obtained at ages 8-9, 13-14, 16-17 and 19-20 both by parent and self-report. Mx modeling was used to estimate additive genetic, shared and specific environmental influences. Genetic continuity was found over the entire developmental period as well as additional sources of genetic influence emerging around early and late adolescence. New unique environmental effects (E) on externalizing behavior arose early in adolescence. The results support both the presence of genetic continuity and change in externalizing behavior during adolescence due to newly emerging genetic and environmental risk factors.

Deconstructing the familiality of variability in momentary negative and positive affect.

OBJECTIVE: The daily life, affective phenotypes of momentary negative affect (NA), positive affect (PA) variability and NA variability are associated with future depressive symptomatology. This study investigates the extent to which genetic and environmental factors contribute to the inter-individual differences in these daily life, affective phenotypes. METHOD: Two hundred and seventy-nine female twins from the Flemish (Belgium) general population participated in an experience sampling study measuring affect in daily life. Structural equation modelling was used to fit univariate and bivariate models. RESULTS: Genetic factors explained, respectively, 18%, 18% and 35% of the inter-individual differences in momentary NA, PA variability and NA variability. Non-shared environmental factors were found to explain the remaining inter-individual variation. In addition, 41% of the association between positive and NA variability was attributed to shared genetic factors. CONCLUSION: Results of this study show that daily life patterns of affective expression are subject to substantial environmental influence. Prospective assessments of the effect of interventions on these expressions may therefore represent a powerful tool to prevent transition from subclinical depressive symptomatology to a clinical outcome or to reduce symptomatology in those with clinical depression.