Rumination is a well-established vulnerability factor for major depressive disorder (MDD) that may exert deleterious effects both independently and in interaction with life stress, and may contribute to the negative memory biases associated with MDD. Chapter 1 examines the role of both momentary ruminative self-focus (MRS) and stress-reactive rumination (SRR) as predictors of increases in depressive symptoms utilizing a smartphone ecological momentary assessment (EMA) design. SRR, but not MRS, independently predicted increases in depressive symptoms. Interactions emerged between negative life events (NLEs) and both MRS and SRR, such that experiencing higher levels of NLEs and rumination at an observation predicted greater increases in depressive symptoms. The results suggest that rumination levels in response to stress vary within individuals and can have an important effect on depressed mood. Chapter 2 tests the hypotheses that 1) engaging in greater SRR relative to an individual’s mean would lead to deeper encoding and improved retrieval of stressors, and 2) this biased memory for negative autobiographical information would predict increases in depressive symptoms over time. NLEs followed by increased SRR relative to individuals’ means were significantly more likely to be recalled two weeks later. In addition, a significant interaction emerged between the number of NLEs experienced and proportional recall of those events, such that individuals who endorsed and recalled greater numbers of stressors during the EMA week displayed increased depressive symptoms at follow-up. These findings support the role of rumination and memory biases as vulnerability factors for depression, and suggest potential clinical benefits of modifying ruminative response styles to daily stressors. / Psychology

This study examined the association between executive functions (EF), trait rumination, and symptoms and diagnosis of unipolar depression in early adolescence. In addition, the current study examined associations between executive functions and risk for depression due to maternal history of depression. Participants were 486 early adolescents (230 males, 256 females; M age = 12.88 years; SD = .62) and their mothers, who were recruited through local schools as part of the Temple University (TU) Adolescent Cognition and Emotion (ACE) Project. Measures included (a) a semi-structured diagnostic interview of mother and adolescent, (b) youth self-report forms assessing depressive symptoms and trait rumination, (c) mother-report forms assessing demographic information and offspring pubertal status, and (d) behavioral tests of EF (sustained, selective and divided attention, attentional set shifting, and working memory). Deficits in executive function were not associated with higher levels of trait rumination. Better sustained attention was marginally significantly positively associated with higher levels of trait rumination after controlling for concurrent depressive symptoms. Conversely, poorer sustained attention was significantly associated with depressive symptoms after controlling for rumination. Gender moderated the set shifting-rumination association, such that better set shifting accuracy was significantly associated with higher levels of trait rumination in boys only. Diagnosis did not moderate EF-rumination associations. No association was found between EF deficits and adolescent lifetime history of unipolar depression. Likewise, no association was found between EF deficits and maternal lifetime history of unipolar depression. In conclusion, findings do not provide evidence that EF deficits are associated with trait rumination in early adolescence, either alone or in interaction with diagnosis or gender. Rather, findings suggest dissociable patterns of association between EF and depression versus rumination and are more consistent with theories postulating that trait rumination is associated with enhanced performance on some tests of EF. In addition, findings do not provide evidence for an association between EF deficits and lifetime history of depression in early adolescence and do not suggest that deficits are present in adolescents at high risk (due to maternal history of disorder) of depression prior to first onset of disorder. Implications and directions for future research are discussed. / Psychology

Rumination consists of voluntary regurgitation of partially digested food, followed by chewing and re-swallowing or expulsion of regurgitated stomach contents (DM-ID2). Little research has systematically analyzed the differential effects of type or quantity of food on rumination across extended observations. This analysis demonstrated that certain (isolated) foods may differentially affect the rate of rumination. Furthermore, patterns of responding and manipulations of quantity may provide evidence for naturally occurring contingencies of punishment for the rumination of particular foods. These results may provide an avenue for minimally invasive, sustainable treatment for individuals with severe and chronic rumination.

Rumination is a well-established risk factor for the onset and maintenance of depression and anxiety and has been identified as a transdiagnostic factor due to its association with multiple forms of psychopathology. A renaissance of psychedelic research shows promise in treating psychopathology with potential for acting on ruminative processes. Despite the growing interest and developments in legality, very few research studies have investigated the psychological consequences of participating in an ayahuasca ceremony in North America. The current study included 30 participants (Mage = 41.03, SD = 7.35; range = 30-59 years; 50.0% women; 76.7% White/Caucasian) who participated in an ayahuasca ceremony at a North American ayahuasca church. Participants were asked to complete seven daily surveys prior to their ceremony (Phase I) and seven daily surveys following their ceremony (Phase II). Multi-level models tested changes in rumination and depression, anxiety, and stress scores across both phases of the study. Significant and large reduction were evidenced in levels of rumination and depression, anxiety, and stress immediately following the ayahuasca ceremony. This effect was maintained during Phase II, with scores remaining lower than Phase I and relatively stable. Furthermore, path models did not support the mediating role of rumination in the negative link between ayahuasca ceremony effects (as indexed via ego-dissolution) and depression, anxiety, and stress scores (though evidence for mediation was found without bootstrapping samples). Findings of this study contribute to the emerging literature on the role that ceremonial ayahuasca use may have on reducing psychological distress.

Deux études ont été initiées dans le but d’évaluer les effets du type de fourrages et du rapport fourrage : concentrés sur la synthèse ruminale de vitamines B. Dans un premier essai, huit vaches Holstein ont été alimentées avec une ration contenant de l’ensilage de luzerne ou de l’ensilage de dactyle comme unique fourrage. Dans un deuxième essai, quatorze vaches Holstein ont été alimentées avec une ration à faible taux de fourrages (44.8%) ou à fort taux de fourrages (64.1%). Utiliser le dactyle comme unique fourrage a augmenté les synthèses ruminales de thiamine, riboflavine, niacine et vitamine B6, mais n’a eu aucun effet sur celle de vitamine B12. Utiliser une ration à bas taux de fourrages a augmenté la synthèse ruminale de thiamine et de niacine, mais a réduit celle de la vitamine B12 tout en diminuant la dégradation ruminale de la vitamine B6. Cette étude est une étape vers l’identification de rations qui nécessiteront une éventuelle supplémentation afin d’optimiser la production laitière. / B-vitamins are synthesized by rumen microflora but knowledge on factors affecting this synthesis is very scarce. Two studies were conducted to determine the effects of dietary factors such as family forage or forage-to-concentrate ratio on B-vitamin ruminal syntheses. In study 1, eight Holstein cows were fed with diets containing either alfalfa or orchardgrass silages as sole forage. In study 2, fourteen Holstein cows were fed low-forage (44.8% forage) or high-forage (64.1% forage) diets. Apparent ruminal synthesis of thiamin, riboflavin, niacin and vitamin B6 were greater with orchardgrass silage than with alfalfa silage. Using a low-forage diet increased ruminal syntheses of thiamin, riboflavin and niacin, reduced vitamin B6 degradation, but decreased ruminal synthesis of vitamin B12. These studies are a step towards identification of diets that may require B-vitamin supplementation to optimize milk production of dairy cows.

本篇研究旨在探討心理反芻思考對個體情緒變化的影響，在類同於Nolen-Hoeksema的前瞻式連續測量架構下劃分不同情緒困擾的時段（整體分析、嚴重又長期情緒不佳的日子、負向情緒發作期），並以Fritz之多向度反芻觀點：功用性反芻、情緒焦點反芻以及意義尋找反芻為切入點，試圖釐清反芻在情緒復原中所扮演的角色利弊。本研究以一般非創傷性的負向事件為研究背景，選取156名大學生在連續十二天的研究設計中，每天測量三類反芻出現的頻率、情緒強度和情緒維持的時間。研究結果顯示，不同內容焦點的反芻思考對事件挫敗後之情緒變化有其獨特的影響效果。整體平均來說，功用性反芻有助於負向情緒的緩解、情緒焦點反芻會增強負向情緒感受、意義尋找反芻則是增加負向情緒維持的時間；若當天處在長期又嚴重情緒不佳日子中時，功用性反芻似有維持正向情緒的效用、情緒焦點反芻則是惡化當天的負向情緒強度、意義尋找反芻則有延長當天負向情緒時間的趨勢；若連續處在長期且嚴重情緒不佳的日子中，功用性反芻對情緒變化並無影響、情緒焦點反芻則是延長且惡化此時期的負向情緒狀態、而意義尋找反芻不但會影響負向情緒的狀態，似也會有助於此時期的正向情緒狀態。因此，本研究結果不僅支持內容區分的必要性；也代表著在情緒復原過程中，配合考量到個體所處的情緒困擾時段時，不同內容焦點的反芻思考對情緒變化的影響是有利弊之分的。 / The purpose of this research is to examine the relation between ruminative thought and mood fluctuation. Similar to the Nolen-Hoeksema’s progressive paradigm, we divided the experimental period into three parts, including average days, severely and long-term negative mood days, and negative mood episode. Combined with the Fritz’s viewpoint of multidimensional rumination ─ instrumental rumination, emotional-focused rumination, and meaning-searching rumination, this research attempted to clarify the role of rumination in the process of emotional recovery. According to the negative but non-traumatic events, we selected 156 college students and daily measured the frequency of three types of rumination, mood intensity, and mood duration during the continuous 12 days. The results of this research showed that different content-focused rumination had unique effect on mood fluctuation after suffering a failure. Generally, instrumental rumination helped to reduce negative mood, emotional-focused rumination worsened negative mood, and meaning-searching rumination increased the duration of negative mood. Moreover, in the period of severely and long-term negative mood status, instrumental rumination seemed to maintain the duration of positive mood, emotional-focused rumination still worsened negative mood, and meaning-searching rumination seemed to prolong the duration of negative mood. Besides, in the period of negative mood episode, instrumental ruminative had no effect on mood fluctuation, emotional-focused rumination deteriorated and extended negative mood, and meaning-searching rumination had harmful effect on the negative mood but still had borderline effect on the positive mood. Consequently, the results of this research not only illustrated the necessary of content-discrimination in the rumination, but also showed that different content-focused rumination had separate effect on the mood fluctuation in the process of emotional recovery, when the three different periods of emotional disturbance were considered.

Mindfulness-based interventions reduce depressive symptoms and rumination, and enhance mindfulness in adults; this non-randomised controlled feasibility study aimed to determine whether these conclusions apply to young people, and whether mindfulness and rumination mediate the effect on depressive symptoms. Participants aged 12-16 received a nine-week universal mindfulness intervention in schools delivered by trained teachers (intervention group, N = 256) or their regular school curriculum (control group, N = 266). Intervention schools were matched to control schools on key variables (publicly-funded versus private, mainstream versus special needs). Young people who received the intervention reported fewer depressive symptoms post-intervention relative to controls, which was maintained at three-month follow-up. Mindfulness and rumination were unchanged immediately after the intervention, however by follow-up, intervention participants were significantly more mindful and less likely to ruminate than controls. The extent to which young people practiced mindfulness was negatively correlated with depressive symptoms at post-intervention and follow-up, positively correlated with mindfulness at post-intervention and follow-up, and positively correlated with rumination at follow-up. This universal mindfulness intervention shows promise for reducing depressive symptoms, reducing rumination and increasing mindfulness in young people, however further research is warranted, particularly regarding the mechanisms of change.

Les pensées répétitives négatives (PRN) sont considérées comme un des processus transdiagnostiques impliqués dans le développement, le maintien et la récurrence de plusieurs troubles psychologiques tels que les troubles de l'humeur, les troubles anxieux ou les addictions. Une des priorités dans les recherches actuelles sur les PRN est de déterminer quel processus contribue au développement et au maintien des PRN inadaptés. La littérature suggère que les déficits d’inhibition et de désengagement attentionnel sont deux facteurs potentiellement impliqués dans la récurrence des PRN. L’objectif de la présente thèse de doctorat était, premièrement de systématiser les recherches antérieures sur le lien entre les PRN et l’inhibition. Deuxièmement nous avons testé dans des études expérimentales comment l’induction des PRN affectait l’inhibition et le désengagement attentionnel.Le premier article expérimental présente une série d’études testant l’impact des PRN sur l’efficacité de l’inhibition. Le second article expérimental montre comment l’induction des PRN affecte le désengagement attentionnel. Une plus-value des études présentées dans cette thèse est la différenciation faite entre les PRN constructives (concrètes expérientielles) et non constructives (abstraites analytiques) dans la procédure d’induction.Les résultats suggèrent que les pensées analytiques abstraites interfèrent avec la régulation émotionnelle dans une situation de problème non résolu. Contrairement aux prédictions, il semble que les pensées abstraites favorisent les processus inhibiteurs et attentionnels dans le traitement des stimuli verbaux.Les résultats sont discutés selon la perspective de la théorie du mode de traitement et de la théorie de dérégulation du niveau objectif/action. Une nouvelle approche des fonctions exécutives dans les PRN est également proposée : l’hypothèse de l’allocation des ressources cognitives dirigée par le mode de traitement. / Repetitive negative thinking (RNT) is one of the transdiagnostic processes involved in development, recurrence and relapse of various psychological disorders, i.e. mood disorders, or anxiety disorders. One of the priorities in the current RNT research is to identify the mechanisms responsible for RNT development and maintain. RNT theory and previous research identified inhibition and attentional disengagement impairment as two potential factors of RNT recurrence.The first aim of the dissertation was to systematize previous research exploring the relation between RNT and inhibition. The second aim was to experimentally test how RNT induction affects both, inhibition and attentional disengagement. The first two chapters present RNT concept itself and a systematic literature review on the links between RNT and inhibition. The following chapters are composed of two empirical articles. The first article presents three experimental studies exploring the impact of RNT induction on inhibition efficiency. The second article tests experimentally how RNT affects attentional disengagement. An important contribution of these experimental studies lays also in testing separately constructive (concrete experiential) and unconstructive (abstract analytic) RNT processing mode.The results suggest that abstract analytic thinking impairs emotional regulation in a non-resolved problem situation – a situation predicted to activate RNT. Contrarily to the predictions, it seems that abstract analytic processing enhances inhibition and attentional performance for verbal stimuli comparing to concrete processing.These results are discussed at the theoretical level in the processing mode theory and deregulation of goal/action level perspective. We provide also methodological recommendation for the further research on the link between RNT and executive functions. Finally, we propose a new framework for the hypothesis of processing mode driven resource allocation in RNT.

Objective: Little epidemiological evidence exists on rumination disorder behavior (RB) and pica behavior (PB). We examined prevalence of RB and PB and presence of comorbid feeding/eating disorder symptoms among school-aged children. Methods: In elementary schools in Switzerland, 1,430 children (54.0% female) ages seven to 13 completed Eating Disorder Examination-Questionnaire for children (ChEDE-Q) and Eating Disturbances in Youth Questionnaire (EDY-Q). Results: EDY-Q data behavior frequency showed 9.7% reported RB only, 10.0% reported PB only, and 3.1% reported RB+PB (≥1 on 0-6 Likert scale). At a clinical cut-off score of ≥4 (at least “often true”), 1.7% had RB only, 3.8% had PB only, and 1.1% had RB+PB. Avoidant/restrictive food intake disorder symptoms were most common in those with RB+PB, and more common in those with RB or PB than those without. Degree of eating disorder symptoms (by ChEDE-Q) over the past 28 days were similar among those with RB, PB, or RB+PB, but less common in those without RB or PB. Discussion: RB and PB were commonly reported in our sample of school-aged children, even at a potential clinically significant cut-off. Our findings also suggest that degree of eating disorder symptom comorbidity is similar between those with RB and PB.

Objective: Little epidemiological evidence exists on rumination disorder behavior (RB) and pica behavior (PB). We examined prevalence of RB and PB and presence of comorbid feeding/eating disorder symptoms among school-aged children. Methods: In elementary schools in Switzerland, 1,430 children (54.0% female) ages seven to 13 completed Eating Disorder Examination-Questionnaire for children (ChEDE-Q) and Eating Disturbances in Youth Questionnaire (EDY-Q). Results: EDY-Q data behavior frequency showed 9.7% reported RB only, 10.0% reported PB only, and 3.1% reported RB+PB (≥1 on 0-6 Likert scale). At a clinical cut-off score of ≥4 (at least “often true”), 1.7% had RB only, 3.8% had PB only, and 1.1% had RB+PB. Avoidant/restrictive food intake disorder symptoms were most common in those with RB+PB, and more common in those with RB or PB than those without. Degree of eating disorder symptoms (by ChEDE-Q) over the past 28 days were similar among those with RB, PB, or RB+PB, but less common in those without RB or PB. Discussion: RB and PB were commonly reported in our sample of school-aged children, even at a potential clinically significant cut-off. Our findings also suggest that degree of eating disorder symptom comorbidity is similar between those with RB and PB.