Matthias Siemer

Amygdala volume in major depressive disorder : a meta-analysis of magnetic resonance imaging studies

Major depressive disorder has been associated with volumetric abnormality in the amygdala. In this meta-analysis we examine results from magnetic resonance imaging volumetry studies of the amygdala in depression in order to assess both the nature of the relationship between depression and amygdala volume as well as the influence of extraexperimental factors that may account for significant variability in reported findings. We searched PubMed and ISI Web of Knowledge databases for articles published from 1985 to 2008 that used the wildcard terms ‘Depress*’ and ‘Amygdal*’ in the title, keywords or abstract. From the 13 studies that met inclusion criteria for our meta-analysis, we calculated aggregate effect size and heterogeneity estimates from amygdala volumetric data; we then used meta-regression to determine whether variability in specific extraexperimental factors accounted for variability in findings. The lack of a reliable difference in amygdala volume between depressed and never-depressed individuals was accounted for by a positive correlation between amygdala volume differences and the proportion of medicated depressed persons in study samples: whereas the aggregate effect size calculated from studies that included only medicated individuals indicated that amygdala volume was significantly increased in depressed relative to healthy persons, studies with only unmedicated depressed individuals showed a reliable decrease in amygdala volume in depression. These findings are consistent with a formulation in which an antidepressant-mediated increase in levels of brain-derived neurotrophic factor promotes neurogenesis and protects against glucocorticoid toxicity in the amygdala in medicated but not in unmedicated depression.

Same situation--different emotions: how appraisals shape our emotions.

Appraisal theories of emotion hold that it is the way a person interprets a situation--rather than the situation itself--that gives rise to one emotion rather than another emotion (or no emotion at all). Unfortunately, most prior tests of this foundational hypothesis have simultaneously varied situations and appraisals, making an evaluation of this assumption difficult. In the present study, participants responded to a standardized laboratory situation with a variety of different emotions. Appraisals predicted the intensity of individual emotions across participants. In addition, subgroups of participants with similar emotional response profiles made comparable appraisals. Together, these findings suggest that appraisals may be necessary and sufficient to determine different emotional reactions toward a particular situation.

Effects of Mood on Evaluative Judgements: Influence of Reduced Processing Capacity and Mood Salience

Schwarz and Clore (1983) proposed that the effects of mood on evaluative judgements are due to peoples use of a “feeling heuristic”. Results of the present study suggest that this heuristic is particularly likely to be used under conditions of reduced processing capacity, induced by time pressure and competing task demands, as both factors intensified the effects of mood on evaluative judgements. In addition, previous findings that increasing the salience of a judgement-irrelevant cause disrupts the effects of mood on evaluative judgements were replicated. All of these effects were, however, obtained only when mood was salient to the participants, suggesting that to be effective, mood must exceed a threshold of salience. Taken together, the findings further support the hypothesis that at least in some situations, the effects of moods on evaluative judgements are based on a controlled inference strategy, rather than on automatic priming effects.

Emotion Regulation in Depression and Anxiety: Examining Diagnostic Specificity and Stability of Strategy Use

Many psychological disorders are characterized by difficulties in emotion regulation. It is unclear, however, whether different disorders are associated with the use of specific emotion regulation strategies, and whether these difficulties are stable characteristics that are evident even after recovery. It is also unclear whether the use of specific strategies is problematic across all disorders or whether disorders differ in how strongly strategy use is associated with symptom severity. This study investigated (1) the specificity of use of emotion regulation strategies in individuals diagnosed with current major depressive disorder (MDD), with social anxiety disorder (SAD), and in never-disordered controls (CTL); and (2) the stability of strategy use in formerly depressed participants (i.e., remitted; RMD). Path analysis was conducted to examine the relation between strategy use and symptom severity across diagnostic groups. Compared to the CTL group, participants in both clinical groups endorsed more frequent use of rumination and expressive suppression, and less frequent use of reappraisal. Specific to SAD were even higher levels of expressive suppression relative to MDD, as well as a stronger relation between rumination and anxiety levels. In contrast, specific to MDD were even higher levels of rumination and lower levels of reappraisal. Interestingly, elevated rumination, but not decreased reappraisal, was found to be a stable feature characterizing remitted depressed individuals. These results may provide insight into ways in which emotion regulation strategy use maintains psychological disorders.

Mood-congruent cognitions constitute mood experience.

Three studies tested the assumption of a dispositional theory of moods that mood-related cognitions constitute essential parts of the phenomenal mood experience. In Study 1, after a hot- versus a cold-, sad-, or angry-mood induction, participants reported their momentary moods and their momentary mood-related cognitions. Self-reported moods and mood-related cognitions changed in a strictly parallel fashion in all mood induction groups. A mediation analysis showed that the influences of distraction on moods were completely mediated by changes in mood-related cognitions. Study 2 replicated the central findings of Study 1 with a musical mood induction procedure. Study 3 showed that the findings do not depend on the explicit manipulation of moods. The results support the tested assumption.

The Process of Emotion Inference

Three experiments investigated the process of inferring emotions from brief descriptions of typical eliciting situations, using response time methodology. The initial hypothesis was that emotion inferences are mediated by inferred cognitive appraisals of the eliciting event (concerning e.g., its valence or the responsible agent). This hypothesis was contradicted by the finding of Experiment 1 that emotion judgments are typically made faster than appraisal judgments. To explain this finding, it was hypothesized that emotion judgments are based on automatized (proceduralized) appraisal inferences. This hypothesis was tested in Experiments 2 and 3 using a judgment facilitation paradigm. The results supported the proceduralization hypothesis by demonstrating that appraisal judgments are facilitated by prior emotion judgments.

Flexible control in processing affective and non-affective material predicts individual differences in trait resilience

Trait resilience is a stable personality characteristic that involves the self-reported ability to flexibly adapt to emotional events and situations. The present study examined cognitive processes that may explain individual differences in trait resilience. Participants completed self-report measures of trait resilience, cognitive flexibility and working memory capacity tasks, and a novel affective task-switching paradigm that assesses the ability to flexibly switch between processing the affective versus non-affective qualities of affective stimuli (i.e., flexible affective processing). As hypothesised, cognitive flexibility and flexible affective processing were unique predictors of trait resilience. Working memory capacity was not predictive of trait resilience, indicating that trait resilience is tied to specific cognitive processes rather than overall better cognitive functioning. Cognitive flexibility and flexible affective processing were not associated with other trait measures, suggesting that these flexibility processes are unique to trait resilience. This study was among the first to investigate the cognitive abilities underlying trait resilience.

Power and measures of effect size in analysis of variance with fixed versus random nested factors.

Ignoring a nested factor can influence the validity of statistical decisions about treatment effectiveness. Previous discussions have centered on consequences of ignoring nested factors versus treating them as random factors on Type I errors and measures of effect size (B. E. Wampold & R. C. Serlin). The authors (a) discuss circumstances under which the treatment of nested provider effects as fixed as opposed to random is appropriate; (b) present 2 formulas for the correct estimation of effect sizes when nested factors are fixed; (c) present the results of Monte Carlo simulations of the consequences of treating providers as fixed versus random on effect size estimates, Type I error rates, and power; and (d) discuss implications of mistaken considerations of provider effects for the study of differential treatment effects in psychotherapy research.

Rumination moderates the effects of daily events on negative mood: results from a diary study.

Rumination describes a detrimental response to distress that involves repetitive thoughts about ones emotional state and its causes and potential consequences. Many experimental studies have shown that induced state rumination exacerbates the effect of laboratory stressors on negative affect. The current study examines whether use of rumination in response to specific real-life events moderates the association between unpleasant daily events and negative mood. One hundred fifty-seven undergraduate participants completed daily diaries for six consecutive days. The daily diaries assessed current mood, a survey of unpleasant daily events, and use of rumination in response to the most unpleasant daily event. Data were analyzed with a multilevel random coefficient modeling (MRCM) approach. It was predicted and found that use of rumination in daily life moderates the relation between unpleasant daily events and negative mood. On days when participants reported intense rumination use, higher levels of unpleasant daily events predicted higher levels of negative mood. By contrast, on days when participants reported lower use of rumination, higher levels of unpleasant events were not associated with higher levels of negative mood. This study is the first to demonstrate that real-life use of rumination moderates the relation between unpleasant events and mood in daily life. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

Implicit interpretation biases affect emotional vulnerability: A training study

Cognitive theories of emotion propose that the interpretation of emotion-eliciting situations crucially shapes affective responses. Implicit or automatic biases in these interpretations may hinder emotion regulation and thereby increase risk for the onset and maintenance of psychological disorders. In this study, participants were randomly assigned to a positive or negative interpretation bias training using ambiguous social scenarios. After the completion of the training, a stress task was administered and changes in positive and negative affect and self-esteem were assessed. The results demonstrate that the interpretation bias training was successful in that participants exhibited a tendency to interpret novel scenarios in accordance with their training condition. Importantly, the positive training condition also had a protective effect on self-esteem. Participants in this condition did not exhibit a decrease in self-esteem after the stress task, whereas participants in the negative condition did. These results demonstrate that implicit cognitive biases can be trained and that this training affects self-esteem. Implications of these findings for research on psychopathology and emotion regulation are discussed.