Tobin J. Ehrlich

Background: Childhood trauma is related to an increased number of depressive episodes and more severe depressive symptoms in bipolar disorder. The evaluation of the networks of depressive symptoms—or the patterns of relationships between individual symptoms—among people with bipolar disorder with and without a history of childhood trauma may assist in further clarifying this complex relationship.Methods: Data from over 500 participants from the Heinz C. Prechter Longitudinal Study of Bipolar Disorder were used to construct a series of regularised Gaussian Graphical Models. The networks of individual depressive symptoms—self‐reported (Patient Health Questionnaire—9; n = 543) and clinician‐rated (Hamilton Depression Rating Scale—17; n = 529)—among participants with bipolar disorder with and without a history of childhood trauma (Childhood Trauma Questionnaire) were characterised and compared.Results: Across the sets of networks, depressed mood consistently emerged as a central symptom (as indicated by strength centrality and expected influence); regardless of participants' history of childhood trauma. Additionally, feelings of worthlessness emerged as a key symptom in the network of self‐reported depressive symptoms among participants with—but not without—a history of childhood trauma.Conclusion: The present analyses—although exploratory—provide nuanced insights into the impact of childhood trauma on the presentation of depressive symptoms in bipolar disorder, which have the potential to aid detection and inform targeted intervention development.

Introduction: Cognitive functioning in bipolar disorder is heterogeneous with evidence for multiple subgroups. However, cognitive subgroup change patterns over time remains unknown. While prior work suggests minimal differences in cognitive functioning patterns over time between those with bipolar disorder and controls, group‐based analyses may obscure unique subgroup‐based changes.Material and Methods: Participants diagnosed with bipolar disorder (I, II, NOS; n = 568) and unaffected controls (n = 234) completed baseline, one‐ and five‐year neuropsychological assessments. Data reduction techniques were used to limit the number of neuropsychological variables. Bipolar disorder participant baseline neuropsychological data were entered into hierarchical cluster analyses and resultant clusters were entered in multilevel models, which tested for differences in baseline and longitudinal cognitive changes in cognition among the cluster groups and with controls.Results: Results were consistent with bipolar disorder participants forming three subgroups with high (n = 209), mid (n = 259), and low (n = 100) cognition. These groups were associated with unique clinical characteristics. Multilevel models demonstrated that over a five‐year period, the low group improved, relative to the high and mid groups, and with controls, in auditory memory. Over the five‐year period, the mid group, in comparison with the high group, improved in visual memory; additionally, the high group remained stable, in comparison with a slight decline in the control group, in inhibitory control.Conclusion: These results demonstrate that cognition‐based subgroups of bipolar disorder participants have minimal differences in their longitudinal course in relation to each other and with unaffected controls.

Background: Childhood trauma is associated with greater depression severity among individuals with bipolar disorder. However, the mechanisms that explain the link between childhood trauma and depression severity in bipolar disorder remain poorly understood. The mediational role of attachment insecurity in childhood and adulthood was assessed in the current study.Methods: Participants with bipolar disorder (N = 143) completed measures of childhood trauma (Childhood Trauma Questionnaire), attachment insecurity (Experiences in Close Relationships Scale) and depression severity (Hamilton Depression Rating Scale) as part of the Prechter Longitudinal Study of Bipolar Disorder. A sequential mediation model was tested using path analysis: the direct and indirect effects of childhood trauma on depression severity with attachment insecurity (attachment anxiety and avoidance) in childhood (mother and father) and adulthood (partner) as mediators were estimated.Results: The final path model demonstrated an excellent fit to the data (comparative fit index = 0.996; root mean square error of approximation = 0.021 [90% confidence interval = 0.000–0.073]). Supporting the hypothesised sequential mediation model, maternal attachment anxiety in childhood and romantic attachment avoidance in adulthood partially mediated the relationship between childhood trauma and depression severity; this effect accounted for 12% of the total effect of childhood trauma on depression severity.Conclusion: Attachment insecurity in childhood and adulthood form part of the complex mechanism informing why people with bipolar disorder who have a history of childhood trauma experience greater depression severity. Addressing attachment insecurity represents a valuable psychotherapeutic treatment target for bipolar disorder.

Patients with depression who ruminate repeatedly focus on depressive thoughts; however, there are two cognitive subtypes of rumination, reflection and brooding, each associated with different prognoses. Reflection involves problem-solving and is associated with positive outcomes, whereas brooding involves passive, negative, comparison with other people and is associated with poor outcomes. Rumination has also been related to atypical functional hyperconnectivity between the default mode network and subgenual prefrontal cortex. Repetitive pulse transcranial magnetic stimulation of the prefrontal cortex has been shown to alter functional connectivity, suggesting that the abnormal connectivity associated with rumination could potentially be altered. This study examined potential repetitive pulse transcranial magnetic stimulation prefrontal cortical targets that could modulate one or both of these rumination subtypes. Forty-three patients who took part in a trial of repetitive pulse transcranial magnetic stimulation completed the Rumination Response Scale questionnaire and resting-state functional magnetic resonance imaging. Seed to voxel functional connectivity analyses identified an anticorrelation between the left lateral orbitofrontal cortex (−44, 26, −8;k = 172) with the default mode network-subgenual region in relation to higher levels of reflection. Parallel analyses were not significant for brooding or the RRS total score. These findings extend previous studies of rumination and identify a potential mechanistic model for symptom-based neuromodulation of rumination.