The notion that specific cognitive and emotional processes arise from functionally distinct brain regions has lately shifted toward a connectivity-based approach that emphasizes the role of ...network-mediated integration across regions. The clinical neurosciences have likewise shifted from a predominantly lesion-based approach to a connectomic paradigm-framing disorders as diverse as stroke, schizophrenia (SCZ), and dementia as "dysconnection syndromes". Here we position bipolar disorder (BD) within this paradigm. We first summarise the disruptions in structural, functional and effective connectivity that have been documented in BD. Not surprisingly, these disturbances show a preferential impact on circuits that support emotional processes, cognitive control and executive functions. Those at high risk (HR) for BD also show patterns of connectivity that differ from both matched control populations and those with BD, and which may thus speak to neurobiological markers of both risk and resilience. We highlight research fields that aim to link brain network disturbances to the phenotype of BD, including the study of large-scale brain dynamics, the principles of network stability and control, and the study of interoception (the perception of physiological states). Together, these findings suggest that the affective dysregulation of BD arises from dynamic instabilities in interoceptive circuits which subsequently impact on fear circuitry and cognitive control systems. We describe the resulting disturbance as a "psychosis of interoception".
It has been suggested that certain types of work may increase the risk of common mental disorders, but the exact nature of the relationship has been contentious. The aim of this paper is to conduct ...the first comprehensive systematic meta-review of the evidence linking work to the development of common mental health problems, specifically depression, anxiety and/or work-related stress and to consider how the risk factors identified may relate to each other. MEDLINE, PsychInfo, Embase, the Cochrane Collaboration and grey literature databases were systematically searched for review articles that examined work-based risk factors for common mental health problems. All included reviews were subjected to a quality appraisal. 37 review studies were identified, of which 7 were at least moderate quality. 3 broad categories of work-related factors were identified to explain how work may contribute to the development of depression and/or anxiety: imbalanced job design, occupational uncertainty and lack of value and respect in the workplace. Within these broad categories, there was moderate level evidence from multiple prospective studies that high job demands, low job control, high effort–reward imbalance, low relational justice, low procedural justice, role stress, bullying and low social support in the workplace are associated with a greater risk of developing common mental health problems. While methodological limitations continue to preclude more definitive statements on causation between work and mental disorders, there is now a range of promising targets for individual and organisational-level interventions aimed at minimising mental health problems in the workplace.
Abstract Those exposed to suicide are at increased risk of adverse outcomes including mental illness, impaired social functioning, and fatal and non-fatal suicidal behavior. However, it is unclear ...how many people are exposed to suicide in the general community. This first meta-analysis of population-based studies aimed to provide pooled estimates of past-year and lifetime prevalence of exposure to suicide among family, friends/peers, and all relationships. In addition, the study examined prevalence of exposure to suicide by age group: adolescents and adults. Systematic searches of the literature in Embase, Medline and PsycINFO identified eighteen studies that were included in the analysis. Pooled past-year prevalence was 4.31% (CI: 2.50 to 6.58) and life-time prevalence 21.83% (CI: 16.32 to 27.90). Both past-year and lifetime prevalences of exposure to suicide among friends and peers were significantly higher than the prevalence of exposure within families; there were no differences in the prevalence of exposure to suicide between adolescents and adults. Heterogeneity was highly significant. Future research should be conducted with large national representative samples and use standardised assessment instruments. Given the increased risks of adverse outcomes among those exposed to suicide, the high rate of exposure to suicide reported here has important ramifications for public health and mental health service delivery.
Stigma has been found to have an impact on those living with bipolar disorder, with many experiencing negative consequences of stereotypes, prejudice and discrimination as a result of their ...condition. The aim of this review was to assess the current literature in bipolar disorder to determine the impact of stigma on people living with this condition and caregivers. Public stigma was associated with greater functional impairment, anxiety and poorer work-related outcomes, while self-stigma was also found to be associated with lower levels of functioning across a range of domains and greater depressive and anxiety symptoms. For those with bipolar disorder, public stigma was reported at similar rates to those with schizophrenia and depression in some studies, with other studies noting mixed results. Qualitative studies noted that public stigma and discrimination were experienced from family, friends and healthcare providers. Self-stigma was found to be higher for those who were younger in several studies and associated with worse medication adherence. It was generally found to be higher in bipolar disorder participants than in those with anxiety disorders and lower than those with personality disorders. Limitations of the current research include the following: few studies have used a longitudinal design, few have assessed the impact of stigma on medication adherence and few have explored these issues in younger populations. More research is needed to explore the experiences of self-stigma for those in the younger age group specifically, given the relationship between younger age and greater self-stigma noted in several studies and the relationship between this and lower treatment adherence.
Traveling patterns of neuronal activity-brain waves-have been observed across a breadth of neuronal recordings, states of awareness, and species, but their emergence in the human brain lacks a firm ...understanding. Here we analyze the complex nonlinear dynamics that emerge from modeling large-scale spontaneous neural activity on a whole-brain network derived from human tractography. We find a rich array of three-dimensional wave patterns, including traveling waves, spiral waves, sources, and sinks. These patterns are metastable, such that multiple spatiotemporal wave patterns are visited in sequence. Transitions between states correspond to reconfigurations of underlying phase flows, characterized by nonlinear instabilities. These metastable dynamics accord with empirical data from multiple imaging modalities, including electrical waves in cortical tissue, sequential spatiotemporal patterns in resting-state MEG data, and large-scale waves in human electrocorticography. By moving the study of functional networks from a spatially static to an inherently dynamic (wave-like) frame, our work unifies apparently diverse phenomena across functional neuroimaging modalities and makes specific predictions for further experimentation.
Densely seeded probabilistic tractography yields weighted networks that are nearly fully connected, hence containing many spurious fibers. It is thus necessary to prune spurious connections from ...probabilistically-derived networks to obtain a more reliable overall estimate of the connectivity. A standard method is to threshold by weight, keeping only the strongest edges. Here, by measuring the consistency of edge weights across subjects, we propose a new thresholding method that aims to reduce the rate of false-positives in group-averaged connectivity matrices. Close inspection of the relationship between consistency, weight, and distance suggests that the most consistent edges are in fact those that are strong for their length, rather than simply strong overall. Hence retaining the most consistent edges preserves more long-distance connections than traditional weight-based thresholding, which penalizes long connections for being weak regardless of anatomy. By comparing our thresholded networks to mouse and macaque tracer data, we also show that consistency-based thresholding exhibits the species-invariant exponential decay of connection weights with distance, while weight-based thresholding does not. We also show that consistency-based thresholding can be used to identify highly consistent and highly inconsistent subnetworks across subjects, enabling more nuanced analyses of group-level connectivity than just the mean connectivity.
•Thresholding is a common method for pruning networks.•We developed a novel method for thresholding networks by intersubject consistency.•Consistent edges tend to be those that are strong for their length, rather than strong overall.•Our method replicates in an independent dataset.•Consistent edges have similar distance dependence to mouse and macaque tracer data.
Background In nonhuman mammals, oxytocin has a critical role in peer recognition and social approach behavior. In humans, oxytocin has been found to enhance trust and the ability to interpret the ...emotions of others. It has been suggested that oxytocin may enhance facial processing by increasing focus on the eye region of human faces. Methods In a double-blind, randomized, placebo-controlled, between-subject design, we tracked the eye movements of 52 healthy male volunteers who were presented with 24 neutral human faces after intranasal administration of 24 IU oxytocin or placebo. Results Participants given oxytocin showed an increased number of fixations and total gaze time toward the eye region compared with placebo participants. Conclusions Oxytocin increases gaze specifically toward the eye region of human faces. This may be one mechanism by which oxytocin enhances emotion recognition, interpersonal communication, and social approach behavior in humans. Findings suggest a possible role for oxytocin in the treatment of disorders characterized by eye-gaze avoidance and facial processing deficits.
Objectives
To identify clinical characteristics and adverse outcomes associated with an earlier age of onset of bipolar disorder.
Methods
A comprehensive search yielded 15 empirical papers comparing ...clinical presentation and outcomes in individuals with bipolar disorder grouped according to age of onset (total N=7370). The following variables were examined to determine odds ratios (ORs) and 95% confidence intervals (CIs): presence of Axis I comorbidity, rapid cycling, psychotic symptoms, mixed episodes (DSM‐IV), lifetime suicide attempts, lifetime alcohol and substance abuse, symptom severity, and treatment delay.
Results
Early age of onset was found to be associated with longer delay to treatment (Hedges’ g=0.39, P=.001), greater severity of depression (Hedges’ g=0.42, P<.001), and higher levels of comorbid anxiety (OR=2.34, P<.001) and substance use (OR=1.80, P<.001). Surprisingly, no association was found between early age of onset and clinical characteristics such as psychotic symptoms or mixed episodes as defined by DSM‐IV.
Conclusions
Earlier age of onset of bipolar disorder is associated with factors that can negatively impact long‐term outcomes such as increased comorbidity. However, no association was found between early onset and indicators of severity or treatment resistance such as psychotic symptoms. Clinical features found to have the strongest relationship with early age of onset were those potentially amenable to pharmacological and psychological treatment. Results highlight the importance of early identification and provide potential areas of focus for the development of early intervention in bipolar disorder.
•There are few studies that have been conducted, with only two randomized controlled trials identified in the review.•Reduced time to relapse and reduced symptoms of anxiety, depression and ...hypo/mania were found in some studies.•More work is needed to explore how interventions may prevent the development of bipolar disorder for young people at risk. Further qualitative research is also required to explore participant experiences of the programs and if engagement is experienced positively.
Several studies have recently been conducted that have explored the benefits of psychological interventions in reducing symptomatology or improving outcomes in young people at-risk of developing bipolar disorder. The aim of this review was to explore if such interventions reduce current psychiatric symptoms and prevent the development of new symptoms.
A systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Databases searched were MEDLINE, EMBASE, PsychInfo, CINAHL and SCOPUS from January 1990 until August 2018. The inclusion criteria were young people aged under 30 years with a family history of bipolar disorder and any empirical studies that contained a psychological or psychoeducation intervention.
A total of 7 articles (N = 138, 55 males) were included (mean age ranged from 12 to 15 years). Interventions conducted included Family Focussed Therapy, Interpersonal and Social Rhythm Therapy, and Mindfulness-based Cognitive Therapy for Children. Significant results were found in some studies, depending on the sample's initial symptoms, with reduced time to relapse and reduced symptoms of anxiety, depression and hypo/mania being found.
No studies have explored if interventions may delay the time to onset of first hypo/manic episodes and only two randomised controlled trials were identified.
Some significant results were noted with lower symptoms of anxiety, depression and hypo/mania being found in some studies. It is currently unclear if psychological interventions may prevent the development of bipolar disorder or other psychiatric symptoms over time; further longitudinal studies are required.
The human connectome is a topologically complex, spatially embedded network. While its topological properties have been richly characterized, the constraints imposed by its spatial embedding are ...poorly understood. By applying a novel resampling method to tractography data, we show that the brain's spatial embedding makes a major, but not definitive, contribution to the topology of the human connectome. We first identify where the brain's structural hubs would likely be located if geometry was the sole determinant of brain topology. Empirical networks show a widespread shift away from this geometric center toward more peripheral interconnected skeletons in each hemisphere, with discrete clusters around the anterior insula, and the anterior and posterior midline regions of the cortex. A relatively small number of strong inter-hemispheric connections assimilate these intra-hemispheric structures into a rich club, whose connections are locally more clustered but globally longer than predicted by geometry. We also quantify the extent to which the segregation, integration, and modularity of the human brain are passively inherited from its geometry. These analyses reveal novel insights into the influence of spatial geometry on the human connectome, highlighting specific topological features that likely confer functional advantages but carry an additional metabolic cost.
•Geometry is crucial to the study of the structural connectome.•We developed a novel method for generating geometry-preserving surrogate networks.•Spatial null models show that geometry strongly contributes to network topology.•Rich club nodes are more peripheral than if they were dictated solely by geometry.
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