The verbal nature of worry in generalized anxiety: Insights from the brain

Alterations in neural circuit dynamics between the limbic network and prefrontal/default mode network in patients with generalized anxiety disorder

BACKGROUND

Widespread functional alterations have been implicated in patients with generalized anxiety disorder (GAD). However, most studies have primarily focused on static brain network features in patients with GAD. The current research focused on exploring the dynamics within functional brain networks among individuals diagnosed with GAD.

METHODS

Seventy-five participants were divided into patients with GAD and healthy controls (HCs), and resting-state functional magnetic resonance imaging data were collected. The severity of symptoms was measured using the Hamilton Anxiety Scale and the Patient Health Questionnaire. Co-activation pattern (CAP) analysis, centered on the bed nucleus of the stria terminalis, was applied to explore network dynamics. The capability of these dynamic characteristics to distinguish between patients with GAD and HCs was evaluated using a support vector machine.

RESULTS

Patients with GAD exhibited disruptions in the limbic-prefrontal and limbic-default-mode network circuits. Particularly noteworthy was the marked reduction in dynamic indicators such as occurrence, EntriesFromBaseline, ExitsToBaseline, in-degree, out-degree, and resilience. Moreover, these decreased dynamic features effectively distinguished the GAD group from the HC in this study.

CONCLUSIONS

The current findings revealed the underlying brain networks associated with compromised emotion regulation in individuals with GAD. The dynamic reduction in connectivity between the limbic-default mode network and limbic-prefrontal networks could potentially act as a biomarker and therapeutic target for GAD in the future.

Visual worry in patients with schizophrenia

OBJECTIVE

Worrying is a pervasive transdiagnostic symptom in schizophrenia. It is most often associated in the literature with verbal modality due to many studies of its presence in generalised anxiety disorder. The current study aimed to elucidate worry in different sensory modalities, visual and verbal, in individuals with schizophrenia.

METHOD

We tested persons with schizophrenia (n = 92) and healthy controls (n = 138) in a cross-sectional design. We used questionnaires of visual and verbal worry (original Worry Modality Questionnaire), trait worry (Penn State Worry Questionnaire) and general psychopathology symptoms (General Functioning Questionnaire-58 and Brief Psychiatric Rating Scale).

RESULTS

Both visual and verbal worry were associated with psychotic, anxiety and general symptoms of psychopathology in both groups with medium to large effect sizes. Regression analyses indicated that visual worry was a single significant predictor of positive psychotic symptoms in a model with verbal and trait worry, both in clinical and control groups (β's of 0.49 and 0.38, respectively). Visual worry was also a superior predictor of anxiety and general psychopathology severity (β's of 0.34 and 0.37, respectively) than verbal worry (β's of 0.03 and -0.02, respectively), under control of trait worry, in the schizophrenia group. We also proposed two indices of worry modality dominance and analysed profiles of dominating worry modality in both groups.

CONCLUSIONS

Our study is the first to demonstrate that visual worry might be of specific importance for understanding psychotic and general psychopathology symptoms in persons with schizophrenia.

Higher Consumption of Fruit and Vegetables Is Associated With Lower Worries, Tension and Lack of Joy Across the Lifespan

Background and Aims

Higher total fruit and vegetable (FV) intakes have been associated with lower perceived stress. However, the relationship of FV intake with domains of perceived stress is unclear. The aim of this cross-sectional study was to explore the relationship between consumption of FV and four perceived stress domains (worries, tension, lack of joy and demands) in a population-based cohort of Australian adults.

Methods

Participants (n = 8,640) were men and women aged ≥25 years from the Australian Diabetes, Obesity and Lifestyle (AusDiab) Study. Dietary intake was assessed using a 74-item validated Food Frequency Questionnaire. Perceived stress domains were determined using a validated 20-item version of the Perceived Stress Questionnaire, with higher scores representing higher perceived stress. Cut-offs for high perceived stress domains were obtained from the highest quartiles of each domain for each sex. Multivariable-adjusted logistic regression was performed to investigate cross-sectional associations.

Results

The mean age of participants (50.1% females) was 47.8 (SD 15) years. Those with higher intakes of FV, combined and separately, had a significantly lower odds (16–36%) for higher worries, tension and lack of joy, independent of other lifestyle factors.

Conclusion

In Australian adults, higher consumption of FV was associated with lower odds of worries, tension and lack of joy. Following the dietary guidelines for the recommended intake of FV may help improve feelings of worries, tension and lack of joy, which are linked to mental health problems.

Repetitive Negative Thinking Processes Account for Gender Differences in Depression and Anxiety During Adolescence

Rumination and worry are vulnerability factors involved in the early development of depression and anxiety during adolescence, particularly in girls. Current views conceptualize rumination and worry as transdiagnostic forms of repetitive negative thinking (RNT). However, most of research has analyzed them separately, without considering gender differences. We analyzed common and specific roles of rumination and worry in accounting for depressive and anxiety symptom levels overall and as a function of gender in adolescents (N = 159). Rumination and worry items were loaded into separate RNT factors. Girls showed a higher use of rumination and worry and higher levels of depression and anxiety than boys. Structural equation modeling supported that both RNT factors accounted for gender differences in symptom levels: rumination was the strongest mediator for depression and worry the strongest mediator for anxiety. Our findings support both general and specific contributions of RNT to account for affective symptomatology during adolescence, particularly in girls.

The Benefits of Music Listening for Induced State Anxiety: Behavioral and Physiological Evidence

BACKGROUND

Some clinical studies have indicated that neutral and happy music may relieve state anxiety. However, the brain mechanisms by which these effective interventions in music impact state anxiety remain unknown.

METHODS

In this study, we selected music with clinical effects for therapy, and 62 subjects were included using the evoked anxiety paradigm. After evoking anxiety with a visual stimulus, all subjects were randomly divided into three groups (listening to happy music, neutral music and a blank stimulus), and EEG signals were acquired.

RESULTS

We found that different emotional types of music might have different mechanisms in state anxiety interventions. Neutral music had the effect of alleviating state anxiety. The brain mechanisms supported that neutral music ameliorating state anxiety was associated with decreased power spectral density of the occipital lobe and increased brain functional connectivity between the occipital lobe and frontal lobe. Happy music also had the effect of alleviating state anxiety, and the brain mechanism was associated with enhanced brain functional connectivity between the occipital lobe and right temporal lobe.

CONCLUSIONS

This study may be important for a deep understanding of the mechanisms associated with state anxiety music interventions and may further contribute to future clinical treatment using nonpharmaceutical interventions.

Exploring patterns of ongoing thought under naturalistic and conventional task-based conditions

Previous research suggests that patterns of ongoing thought are heterogeneous, varying across situations and individuals. The current study investigated the influence of multiple tasks and affective style on ongoing patterns of thought. We used 9 different tasks and measured ongoing thought using multidimensional experience sampling. A Principal Component Analysis of the experience sampling data revealed four patterns of ongoing thought: episodic social cognition, unpleasant intrusive, concentration and self focus. Linear Mixed Modelling was used to conduct a series of exploratory analyses aimed at examining contextual distributions of these thought patterns. We found that different task contexts reliably evoke different thought patterns. Moreover, intrusive and negative thought pattern expression were influenced by individual affective style (depression level). The data establish the influence of task context and intrinsic features on ongoing thought, highlighting the importance of documenting how thought patterns emerge in cognitive tasks with different requirements.

Cognitive behavioral based group psychotherapy focusing on repetitive negative thinking: Decreased uncontrollability of rumination is related to brain perfusion increases in the left dorsolateral prefrontal cortex

Repetitive negative thinking (RNT) is a core process underlying various psychiatric disorders. 'Uncontrollability of rumination (UOR)' is one the most maladaptive factors of rumination, but little is known on how cognitive behavioral focused RNT psychotherapy may alter brain activity. In a subsample of 47 patients suffering from RNT who also underwent brain imaging (registered RCT trial NCT01983033), we evaluated the effect of cognitive behavioral based group psychotherapy (CBGP) (n = 25) as compared to a delayed treatment control group (DTCG) (n = 22) on frontolimbic brain perfusion with a focus on UOR. This RNT construct was measured using the subscale 'uncontrollability' of the Dutch version of the Rumination on Sadness Scale (LARSS-U). Brain perfusion was assessed with arterial spin labeling (ASL)-fMRI. LARSS-U scale scores significantly decreased in the CBGP cohort whereas no significant changes emerged in the DTCG group. Compared to the DTCG, this decrease on UOR in the CBGP group was related to significant perfusion increases in the left (dorsolateral) prefrontal cortex, part of the executive network. Besides the fact that CBGP significantly reduced RNT, this attenuation of uncontrollable ruminative thoughts was related to brain perfusion increases areas documented to be involved in the top down control of adaptive emotion regulation and the inhibition of ruminative processes.

Interactions between the neural correlates of dispositional internally directed thought and visual imagery

Cognition is not always directed to the events in the here and now and we often self-generate thoughts and images in imagination. Important aspects of these self-generated experiences are associated with various dispositional traits. In this study, we explored whether these psychological associations relate to a common underlying neurocognitive mechanism. We acquired resting state functional magnetic resonance imaging data from a large cohort of participants and asked them to retrospectively report their experience during the scan. Participants also completed questionnaires reflecting a range of dispositional traits. We found thoughts emphasizing visual imagery at rest were associated with dispositional tendency towards internally directed attention (self-consciousness and attentional problems) and linked to a stronger correlation between a posterior parietal network and a lateral fronto-temporal network. Furthermore, decoupling between the brainstem and a lateral visual network was associated with dispositional internally directed attention. Critically, these brain-cognition associations were related: the correlation between parietal-frontal regions and reports of visual imagery was stronger for individuals with increased connectivity between brainstem and visual cortex. Our results highlight neural mechanisms linked to the dispositional basis for patterns of self-generated thought, and suggest that accounting for dispositional traits is important when exploring the neural substrates of self-generated experience (and vice versa). This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.

Uncovering complex central autonomic networks at rest: a functional magnetic resonance imaging study on complex cardiovascular oscillations

This study aims to uncover brain areas that are functionally linked to complex cardiovascular oscillations in resting-state conditions. Multi-session functional magnetic resonance imaging (fMRI) and cardiovascular data were gathered from 34 healthy volunteers recruited within the human connectome project (the '100-unrelated subjects' release). Group-wise multi-level fMRI analyses in conjunction with complex instantaneous heartbeat correlates (entropy and Lyapunov exponent) revealed the existence of a specialized brain network, i.e. a complex central autonomic network (CCAN), reflecting what we refer to as complex autonomic control of the heart. Our results reveal CCAN areas comprised the paracingulate and cingulate gyri, temporal gyrus, frontal orbital cortex, planum temporale, temporal fusiform, superior and middle frontal gyri, lateral occipital cortex, angular gyrus, precuneous cortex, frontal pole, intracalcarine and supracalcarine cortices, parahippocampal gyrus and left hippocampus. The CCAN visible at rest does not include the insular cortex, thalamus, putamen, amygdala and right caudate, which are classical CAN regions peculiar to sympatho-vagal control. Our results also suggest that the CCAN is mainly involved in complex vagal control mechanisms, with possible links with emotional processing networks.

Systematic review and meta-analyses of neural structural and functional differences in generalized anxiety disorder and healthy controls using magnetic resonance imaging

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PFC-amygdala FC is altered in GAD, indicating top-down processing deficits.

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GAD had reduced activity for emotion regulation and working memory in the culmen.

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Salience, default, and central executive nodes have altered structure and function.

Objective

To compare structure, functional connectivity (FC) and task-based neural differences in subjects with generalized anxiety disorder (GAD) compared to healthy controls (HC).

Methods

The Embase, Ovid Medline, PsycINFO, Scopus, and Web of Science databases were searched from inception until March 12, 2018. Two reviewers independently screened titles, abstracts, and full-text articles. Data were extracted from records directly contrasting GAD and HC that included structure (connectivity and local indices such as volume, etc.), FC, or task-based magnetic resonance imaging data. Meta-analyses were conducted, as applicable, using AES-SDM software.

Results

The literature search produced 4,645 total records, of which 85 met the inclusion criteria for the systematic review. Records included structural (n = 35), FC (n = 33), and task-based (n = 42) findings. Meta-analyses were conducted on voxel-based morphometry and task-based results.

Discussion

The systematic review confirms and extends findings from previous reviews. Although few whole-brain resting state studies were conducted, key nodes of resting state networks have altered physiology: the hippocampus (default network), ACC and amygdala (salience network), have reduced volume, and the dlPFC (central executive network) and ACC have reduced FC with the amygdala in GAD. Nodes in the sensorimotor network are also altered with greater pre- and postcentral volume, reduced supplementary motor area volume, and reduced FC in anterior and increased FC in posterior cerebellum.

Conclusions

Despite limitations due to sample size, the meta-analyses highly agree with the systematic review and provide evidence of widely distributed neural differences in subjects with GAD, compared to HC. Further research optimized for meta-analyses would greatly improve large-scale comparisons.

Individual variation in patterns of task focused, and detailed, thought are uniquely associated within the architecture of the medial temporal lobe

Understanding the neural processes that support different patterns of ongoing thought is an important goal of contemporary cognitive neuroscience. Early accounts assumed the default mode network (DMN) was especially important for conscious attention to task-irrelevant/personally relevant materials. However, simple task-negative accounts of the DMN are incompatible with more recent evidence that neural patterns within the system can be related to ongoing processing during active task states. To better characterise the contribution of the DMN to ongoing thought, we conducted a cross-sectional analysis of the relationship between the structural organisation of the brain, as indexed by cortical thickness, and patterns of experience, identified using experience sampling in the cognitive laboratory. In a sample of 181 healthy individuals (mean age 20 years, 117 females) we identified an association between cortical thickness in the anterior parahippocampus and patterns of task focused thought, as well as an adjacent posterior region in which cortical thickness was associated with experiences with higher levels of subjective detail. Both regions fell within regions of medial temporal lobe associated with the DMN, yet varied in their functional connectivity: the time series of signals in the 'on-task' region were more correlated with systems important for external task-relevant processing (as determined by meta-analysis) including the dorsal and ventral attention, and fronto-parietal networks. In contrast, connectivity within the region linked to subjective 'detail' was more correlated with the medial core of the DMN (posterior cingulate and the medial pre-frontal cortex) and regions of primary visual cortex. These results provide cross-sectional evidence that confirms a role of the DMN in how detailed experiences are and so provide further evidence that the role of this system in experience is not simply task-irrelevant. Our results also highlight processes within the medial temporal lobe, and their interactions with other regions of cortex, as important in determining multiple aspects of how human cognition unfolds.

A review of neuroimaging studies in generalized anxiety disorder: "So where do we stand?"

Generalized anxiety disorder (GAD) is a prevalent anxiety disorder, but is still poorly recognized in clinical practice. The aim of this review is to provide a coherent understanding of the functional neuroanatomy of GAD; second, to discuss the current theoretical cognitive models surrounding GAD; and finally to discuss the discrepancy between fundamental research and clinical practice and highlight several potential directions for future research in this domain. A systematic review of original papers investigating the neural correlates of DSM-IV and DSM-5 defined GAD samples was undertaken in Ovid literature search, PubMed, Medline, EMbase, PsycINFO, Google Scholar, and TRIP databases. Articles published between 2007 and 2018 were included. First, GAD seems to be characterized by limbic and (pre)frontal abnormalities. More specifically, GAD patients show difficulties in engaging the prefrontal cortex (PFC) and anterior cingulate cortex (ACC) during emotional regulation tasks. Second, the involved brain areas appear to be characterized by heterogeneity possibly due to a variety of experimental designs and test subjects. Third, regarding the discrimination between GAD and other anxiety disorders via fMRI, results appear to be mixed. Studies report both GAD-specific activity and an inability to differentiate between GAD and other anxiety or mood disorders. The usage of different experimental tasks, test subjects, outcome measures and experimental designs limits the possibilities of generalizing results as well as conducting meta-analytical research. Certain theoretical models of GAD describe our understanding of this disorder and form the basis for treatment interventions. However, fMRI research thus far has failed to validate these models. To bridge the gap between fundamental research and clinical practice in GAD, we propose that fMRI researchers make an effort to validate the existing cognitive model of GAD. An alternative approach could be that new models would be based on current neuroimaging research as well as convergent research methods such as Heart Rate Variability (a bottom up approach).

A quantitative meta-analysis of fMRI studies investigating emotional processing in excessive worriers: Application of activation likelihood estimation analysis

BACKGROUND

Excessive worry is a highly impairing cognitive activity which features a range of psychological disorders. Investigations of its disturbed underlying neural mechanisms have presented largely heterogeneous results. This quantitative neuroimaging meta-analysis aims to identify consistent functional disturbances in emotional processing associated with excessive worry across previously published studies.

METHODS

We used the activation likelihood estimation (ALE) method to test for significant convergence across findings of 16 neuroimaging experiments reporting functional aberrations during emotional processing between individuals experiencing high versus normal levels of worry.

RESULTS

Results demonstrated convergent aberrations in high compared to normal worriers mainly in a left-hemispheric cluster comprising parts of the middle frontal gyrus, inferior frontal gyrus and anterior insula. Behavioral characterization indicated the identified cluster to be associated with language processing and memory, while meta-analytic connectivity mapping yielded strong functional connections between the observed convergent regions and parts of the salience network as well as the default mode network.

LIMITATIONS

The ALE method cannot consider findings based on regions of interest analyses and studies without significant group differences.

CONCLUSION

Our results indicate that in response to emotional contexts worry prone individuals exhibit disturbed functioning in brain areas which are possibly associated with deviant inner speech processes experienced by these individuals. The observed clusters may further constitute key nodes within interacting neural networks that support internally and externally oriented cognition and control the dynamic interplay among these processes.

The spark that might have ignited the fire: The association of cognitive and psychological factors with state anxiety in light of the Syrian-Israeli incident

The current study aimed to explore Israelis' state anxiety due to a Syrian-Israeli incident that occurred on February 10, 2018, when an Israeli F-16 fighter jet was shot down by Syrian air defense forces. In line with the "looming vulnerability" model which emphasizes the importance of the dynamic nature of psychologically threatening situations, the following psychological factors were suggested: associative memory of prior events, worries of future war, sense of safety, and death anxiety. We employed two cross-sectional points of time in our assessment: 36 hours and three months after the incident. Using an online survey, 162 adult participants were recruited in Study 1 and 172 in Study 2. The participants completed set of questionnaires measuring state anxiety along with other psychological measures. The results of the two studies suggested that higher levels of worry of future war and lower levels of sense of safety associated with higher state anxiety. The looming vulnerability model and variables associated with state anxiety were found to have a salient role in explaining state anxiety as a response to a negative unexpected event.

Network abnormalities in generalized anxiety pervade beyond the amygdala-pre-frontal cortex circuit: Insights from graph theory

Generalized anxiety disorder (GAD) has excessive anxiety and uncontrollable worry as core symptoms. Abnormal cerebral functioning underpins the expression and perhaps pathogenesis of GAD:. Studies implicate impaired communication between the amygdala and the pre-frontal cortex (PFC). Our aim was to longitudinally investigate whether such network abnormalities are spatially restricted to this circuit or if the integrity of functional brain networks is globally disrupted in GAD. We acquired resting-state functional magnetic resonance imaging data from 16 GAD patients and 16 matched controls at baseline and after 1 year. Using network modeling and graph-theory, whole-brain connectivity was characterized from local and global perspectives. Overall lower global efficiency, indicating sub-optimal brain-wide organization and integration, was present in patients with GAD compared to controls. The amygdala and midline cortices showed higher betweenness centrality, reflecting functional dominance of these brain structures. Third, lower betweenness centrality and lower degree emerged for PFC, suggesting weakened inhibitory control. Overall, network organization showed impairments consistent with neurobiological models of GAD (involving amygdala, PFC, and cingulate cortex) and further pointed to an involvement of temporal regions. Such impairments tended to progress over time and predict anxiety symptoms. A graph-analytic approach represents a powerful approach to deepen our understanding of GAD.