Functional neuroanatomy of mania

A framework for a brain-derived nosology of psychiatric disorders

Current psychiatric diagnoses are not defined by neurobiological measures which hinders the development of therapies targeting mechanisms underlying mental illness 1,2 . Research confined to diagnostic boundaries yields heterogeneous biological results, whereas transdiagnostic studies often investigate individual symptoms in isolation. There is currently no paradigm available to comprehensively investigate the relationship between different clinical symptoms, individual disorders, and the underlying neurobiological mechanisms. Here, we propose a framework that groups clinical symptoms derived from ICD-10/DSM-V according to shared brain mechanisms defined by brain structure, function, and connectivity. The reassembly of existing ICD-10/DSM-5 symptoms reveal six cross-diagnostic psychopathology scores related to mania symptoms, depressive symptoms, anxiety symptoms, stress symptoms, eating pathology, and fear symptoms. They were consistently associated with multimodal neuroimaging components in the training sample of young adults aged 23, the independent test sample aged 23, participants aged 14 and 19 years, and in psychiatric patients. The identification of symptom groups of mental illness robustly defined by precisely characterized brain mechanisms enables the development of a psychiatric nosology based upon quantifiable neurobiological measures. As the identified symptom groups align well with existing diagnostic categories, our framework is directly applicable to clinical research and patient care.

Striatal functional alterations link to distinct symptomatology across mood states in bipolar disorder

BACKGROUND

As a central hub in cognitive and emotional brain circuits, the striatum is considered likely to be integrally involved in the psychopathology of bipolar disorder (BD). However, it remains unclear how alterations in striatal function contribute to distinct symptomatology of BD during different mood states.

METHODS

Behavioral assessment (i.e., emotional symptoms and cognitive performance) and neuroimaging data were collected from 125 participants comprising 31 (hypo)manic, 31 depressive and 31 euthymic patients with BD, and 32 healthy controls. We compared the functional connectivity (FC) of striatal subregions across BD mood states with healthy controls and then used a multivariate data-driven approach to explore dimensional associations between striatal connectivity and behavioral performance. Finally, we compared the FC and behavioral composite scores, which reflect the individual weighted representation of the associations, among different mood states.

RESULTS

Patients in all mood states exhibited increased FC between the bilateral ventral rostral putamen (VRP) and ventrolateral thalamus. Bipolar (hypo)mania uniquely exhibited increased VRP connectivity and superior ventral striatum connectivity. One latent component was identified, whereby increased FCs of striatal subregions were associated with distinct psychopathological symptomatology (more manic symptoms, elevated positive mood, less depressive symptoms and worse cognitive performance). Bipolar (hypo)manic patients had the highest FC and behavioral composite scores while bipolar depressive patients had the lowest.

CONCLUSIONS

Our data demonstrated both trait features of BD and state features specific to bipolar (hypo) mania. The findings underscored the fundamental role of the striatum in the pathophysiological processes underlying specific symptomatology across all mood states.

Similar imaging changes and their relations to genetic profiles in bipolar disorder across different clinical stages

Bipolar disorder (BD) across different clinical stages may present shared and distinct changes in brain activity. We aimed to reveal the neuroimaging homogeneity and heterogeneity of BD and its relationship with clinical variables and genetic variations. In present study, we conducted fractional amplitude of low-frequency fluctuations (fALFF), functional connectivity (FC) and genetic neuroimaging association analyses with 32 depressed, 26 manic, 35 euthymic BD patients and 87 healthy controls (HCs). Significant differences were found in the bilateral pre/subgenual anterior cingulate cortex (ACC) across the four groups, and all bipolar patients exhibited decreased fALFF values in the ACC when compared to HCs. Furthermore, positive associations were significantly observed between fALFF values in the pre/subgenual ACC and participants' cognitive functioning. No significant changes were found in ACC-based FC. We identified fALFF-alteration-related genes in BD, with enrichment in biological progress including synaptic and ion transmission. Taken together, abnormal activity in ACC is a characteristic change associated with BD, regardless of specific mood stages, serving as a potential neuroimaging feature in BD patients. Our genetic neuroimaging association analysis highlights possible heterogeneity in biological processes that could be responsible for different clinical stages in BD.

A pilot study examining the impact of lithium treatment and responsiveness on mnemonic discrimination in bipolar disorder

INTRODUCTION

Mnemonic discrimination (MD), the ability to discriminate new stimuli from similar memories, putatively involves dentate gyrus pattern separation. Since lithium may normalize dentate gyrus functioning in lithium-responsive bipolar disorder (BD), we hypothesized that lithium treatment would be associated with better MD in lithium-responsive BD patients.

METHODS

BD patients (N = 69; NResponders = 16 [23 %]) performed the Continuous Visual Memory Test (CVMT), which requires discriminating between novel and previously seen images. Before testing, all patients had prophylactic lithium responsiveness assessed over ≥1 year of therapy (with the Alda Score), although only thirty-eight patients were actively prescribed lithium at time of testing (55 %; 12/16 responders, 26/53 nonresponders). We then used computational modelling to extract patient-specific MD indices. Linear models were used to test how (A) lithium treatment, (B) lithium responsiveness via the continuous Alda score, and (C) their interaction, affected MD.

RESULTS

Superior MD performance was associated with lithium treatment exclusively in lithium-responsive patients (Lithium x AldaScore β = 0.257 [SE 0.078], p = 0.002). Consistent with prior literature, increased age was associated with worse MD (β = -0.03 [SE 0.01], p = 0.005).

LIMITATIONS

Secondary pilot analysis of retrospectively collected data in a cross-sectional design limits generalizability.

CONCLUSION

Our study is the first to examine MD performance in BD. Lithium is associated with better MD performance only in lithium responders, potentially due to lithium's effects on dentate gyrus granule cell excitability. Our results may influence the development of behavioural probes for dentate gyrus neuronal hyperexcitability in BD.

Magnetic Seizure Therapy vs Modified Electroconvulsive Therapy in Patients With Bipolar Mania: A Randomized Clinical Trial

Importance

Bipolar mania is a common disabling illness. Electroconvulsive therapy (ECT) is an effective treatment for patients with severe mania, though it is limited by the risk of cognitive adverse effects. Magnetic seizure therapy (MST) as an alternative treatment to ECT for bipolar mania has not yet been reported.

Objective

To compare the effectiveness and cognitive adverse effects of MST and ECT in bipolar mania.

Design, Setting, and Participants

This randomized clinical trial was conducted at the Shanghai Mental Health Center from July 1, 2017, through April 26, 2021. Forty-eight patients with bipolar mania were recruited and randomly allocated to receive MST or ECT. The data analysis was performed from June 5, 2021, through August 30, 2023.

Interventions

Patients completed 2 or 3 sessions of MST or ECT per week for a total of 8 to 10 sessions. The MST was delivered at 100% device output with a frequency of 75 Hz over the vertex.

Main Outcomes and Measures

The primary outcomes were reduction of total Young Manic Rating Scale (YMRS) score and response rate (more than 50% reduction of the total YMRS score compared with baseline). An intention-to-treat (ITT) analysis and repeated-measures analyses of variance were conducted for the primary outcomes.

Results

Twenty patients in the ECT group (mean [SD] age, 31.6 [8.6] years; 12 male [60.0%]) and 22 patients in the MST group (mean [SD] age, 34.8 [9.8] years; 15 male [68.2%]) were included in the ITT analysis. The response rates were 95.0% (95% CI, 85.4%-100%) in the ECT group and 86.4% (95% CI, 72.1%-100%) in the MST group. The YMRS reduction rate (z = -0.82; 95% CI, -0.05 to 0.10; P = .41) and response rate (χ2 = 0.18; 95% CI, -0.13 to 0.31; P = .67) were not significantly different between the groups. The time-by-group interaction was significant for the language domain (F1,24 = 7.17; P = .01), which was well preserved in patients receiving MST but worsened in patients receiving ECT. No serious adverse effects were reported in either group.

Conclusions and Relevance

These findings suggest that MST is associated with a high response rate and fewer cognitive impairments in bipolar mania and that it might be an alternative therapy for the treatment of bipolar mania.

Trial Registration

ClinicalTrials.gov Identifier: NCT03160664.

Steroid-induced mania in a patient with previously well-controlled organic bipolar 1-like affective disorder secondary to acquired brain injury: case report and literature review

Steroid-induced neuropsychiatric sequelae are common, and pose significant risks to people usually receiving glucocorticoids in the context of physical illness. Steroid-induced mania and hypomania are the most common of the acute complications, yet despite great progress in understandings in neurophysiology there are no recent studies which review the factors which might predict who will experience this severe complication, nor are there consensus guidelines on management. We report the unusual case of a woman in her 50s admitted to a psychiatric unit with steroid-induced mania despite compliance with two mood stabilisers, several days after the administration of a Dexamethasone and Docetaxel chemotherapy regime adjunctive to lumpectomy for breast cancer. She had previously been diagnosed with an organic affective disorder (with classical bipolar 1 pattern) following severe ventriculitis related to ventricular drain insertion for obstructive hydrocephalus secondary to a colloid cyst. She had no psychiatric illness before this brain injury, but has a maternal history of idiopathic bipolar 1 affective disorder. Her episode of steroid-induced mania resolved following use of sedative medications, continuation of her existing mood stabilisers, and reductions of the steroid dosing in collaboration with her oncology team, which also protected her from further manic relapses during continued chemotherapy. Established mental illness, a family history, and acquired brain injury may reflect risk factors for steroid-induced mania through currently unclear pathways. Future epidemiological studies could better confirm these observations, and basic neuroscience may look to further explore the role of extrinsic glucocorticoids in the pathophysiology of affective disorders.

Brain functional changes across mood states in bipolar disorder: from a large-scale network perspective

BACKGROUND

Exploring the neural basis related to different mood states is a critical issue for understanding the pathophysiology underlying mood switching in bipolar disorder (BD), but research has been scarce and inconsistent.

METHODS

Resting-state functional magnetic resonance imaging data were acquired from 162 patients with BD: 33 (hypo)manic, 64 euthymic, and 65 depressive, and 80 healthy controls (HCs). The differences of large-scale brain network functional connectivity (FC) between the four groups were compared and correlated with clinical characteristics. To validate the generalizability of our findings, we recruited a small longitudinal independent sample of BD patients (n = 11). In addition, we examined topological nodal properties across four groups as exploratory analysis.

RESULTS

A specific strengthened pattern of network FC, predominantly involving the default mode network (DMN), was observed in (hypo)manic patients when compared with HCs and bipolar patients in other mood states. Longitudinal observation revealed an increase in several network FCs in patients during (hypo)manic episode. Both samples evidenced an increase in the FC between the DMN and ventral attention network, and between the DMN and limbic network (LN) related to (hypo)mania. The altered network connections were correlated with mania severity and positive affect. Bipolar depressive patients exhibited decreased FC within the LN compared with HCs. The exploratory analysis also revealed an increase in degree in (hypo)manic patients.

CONCLUSIONS

Our findings identify a distributed pattern of large-scale network disturbances in the unique context of (hypo)mania and thus provide new evidence for our understanding of the neural mechanism of BD.

Structural and temporal dynamics analysis of neural circuit from 2002 to 2022: A bibliometric analysis

Background

In the pursuit of causal insights into neural circuit functionality, various interventions, including electrical, genetic, and pharmacological approaches, have been applied over recent decades. This study employs a comprehensive bibliometric perspective to explore the field of neural circuits.

Methods

Reviews and articles on neural circuits were obtained from the Web of Science Core Collection (WOSCC) database on Apr. 12, 2023. In this article, co-authorship analysis, co-occurrence analysis, citation analysis, bibliographic analysis, and co-citation analysis were used to clarify the authors, journals, institutions, countries, topics, and internal associations between them.

Results

More than 2000 organizations from 52 different countries published 3975 articles in the field of "neural circuit" were used to analysis. Luo liqun emerged as the most prolific author, and Deisseroth Karl garners the highest co-citations (3643). The Journal of Neuroscience leaded in publications, while Nature toped in citations. Chinese Academy of Science recorded the highest article count institutionally, with Stanford University ranking first with 14,350 citations. Since 2020, neurodynamic, anxiety-related mechanisms, and GABAergic neurons have gained prominence, shaping the trajectory of neural circuitry research.

Conclusions

Our investigation has discerned a paradigmatic reorientation towards neurodynamic processes, anxiety-related mechanisms, and GABAergic neurons within the domain of neural circuit research. This identification intimates a prospective trajectory for the field. In the future, it is imperative for research endeavors to accord priority to the translational application of these discernments, with the aim of materializing tangible clinical solutions.

Imbalanced motivated behaviors according to motor sign asymmetry in drug-naïve Parkinson's disease

Few studies have considered the influence of motor sign asymmetry on motivated behaviors in de novo drug-naïve Parkinson's disease (PD). We tested whether motor sign asymmetry could be associated with different motivated behavior patterns in de novo drug-naïve PD. We performed a cross-sectional study in 128 de novo drug-naïve PD patients and used the Ardouin Scale of Behavior in Parkinson's disease (ASBPD) to assess a set of motivated behaviors. We assessed motor asymmetry based on (i) side of motor onset and (ii) MDS-UPDRS motor score, then we compared right hemibody Parkinson's disease to left hemibody Parkinson's disease. According to the MDS-UPDRS motor score, patients with de novo right hemibody PD had significantly lower frequency of approach behaviors (p = 0.031), including nocturnal hyperactivity (p = 0.040), eating behavior (p = 0.040), creativity (p = 0.040), and excess of motivation (p = 0.017) than patients with de novo left hemibody PD. Patients with de novo left hemibody PD did not significantly differ from those with de novo right hemibody PD regarding avoidance behaviors including apathy, anxiety and depression. Our findings suggest that motor sign asymmetry may be associated with an imbalance between motivated behaviors in de novo drug-naïve Parkinson's disease.

Is brain perfusion correlated to switching mood states and cognitive impairment in bipolar disorder type I? A longitudinal study using perfusion imaging approach

Type I Bipolar disorder (BD-I) is a neuropsychiatric disorder characterized by manic or mixed-featured episodes, impaired cognitive functioning, and persistent work and social functioning impairment. This study aimed to investigate within-subject; (i) differences in brain perfusion using Single-photon emission computed tomography (SPECT) between manic and euthymic states in BD-I patients; (ii) explore potential associations between altered brain perfusion and cognitive status; and (iii) examine the relationship between cerebral perfusion and mania symptom ratings. Seventeen adult patients diagnosed with BD-I in a manic episode were recruited, and clinical assessments, cognitive tests, and brain perfusion studies were conducted at baseline (mania state) and a follow-up visit 6 months later. The results showed cognitive impairment during the manic episode, which persisted during the euthymic state at follow-up. However, no significant changes in brain perfusion were observed between the manic and euthymic states. During mania, trends toward decreased perfusion in the left cerebellum and right superior parietal lobule were noted. Additionally, trends indicated a higher perfusion imbalance in the left superior and middle frontal gyrus during mania and the right superior and middle frontal gyrus during euthymia. No significant correlations existed between brain perfusion, mania symptom ratings, and cognitive performance, indicating that symptomatology might represent more than neural hemodynamics. These findings suggest that cognitive impairment may persist in BD-I patients and highlight the need for therapeutic interventions targeting cognitive deficits. More extensive studies with extended follow-up periods are warranted further to investigate brain perfusion and cognitive functioning in BD-I patients.

Social cognitive deficit is associated with visuomotor coordination impairment and dopamine transporter availability in euthymic bipolar disorder

BACKGROUND

Extensive evidence has suggested functional connections between co-occurring visuomotor and social cognitive deficits in neuropsychiatric disorders; however, such association has not been studied in bipolar disorder (BD). We aimed to investigate the relationship between visuomotor coordination and social cognition in the euthymic stage of BD (euBD). Given the shared neurobiological underpinnings involving the dopaminergic system and corticostriatal circuitry, we hypothesized a positive correlation between social cognition and visuomotor coordination in euBD patients.

METHODS

40 euBD patients and 59 healthy control (HC) participants underwent evaluation of social (Diagnostic Analysis of Nonverbal Accuracy 2-Taiwan version (DANVA-2-TW)), non-social cognitive function and visuomotor coordination. A subgroup of participants completed single-photon emission computed tomography for striatal dopamine transporter (DAT) availability assessment.

RESULTS

EuBD patients showed impaired nonverbal emotion recognition (ps ≤ 0.033) and poorer visuomotor coordination (ps < 0.003) compared to HC, with a positive correlation between these two abilities (r = 0.55, p < 0.01). However, after considering potential confounding factors, instead of visuomotor coordination, striatal DAT availability was a unique predictor of emotion recognition accuracy in euBD (beta = 0.33, p = 0.001).

CONCLUSION

Our study result supported a functional association between social cognition and visuomotor coordination in euBD, with striatal dopaminergic dysfunction emerged as a crucial contributing factor in their interrelation.

Alogia and pressured speech do not fall on a continuum of speech production using objective speech technologies

Speech production is affected in a variety of serious mental illnesses (SMI; e.g., schizophrenia, unipolar depression, bipolar disorders) and at its extremes can be observed in the gross reduction of speech (e.g., alogia) or increase of speech (e.g., pressured speech). The present study evaluated whether clinically-rated alogia and pressured speech represent antithetical constructs when analyzed using objective metrics of speech production. We examined natural speech using acoustic and natural language processing features from two archival studies using several different speaking tasks and a combined 107 patients meeting criteria for SMI. Contrary to expectations, we did not find that alogia and pressured speech presented as opposing ends of a speech production continuum. Objective speech markers were associated with clinically rated alogia but not pressured speech, and these results were consistent across speaking tasks and studies. Implications for our understanding of speech production symptoms in SMI are discussed, as well as implications for Natural Language Processing and digital phenotyping efforts more generally.

Mania-related effects on structural brain changes in bipolar disorder - a narrative review of the evidence

Cross-sectional neuroimaging studies show that bipolar disorder is associated with structural brain abnormalities, predominantly observed in prefrontal and temporal cortex, cingulate gyrus, and subcortical regions. However, longitudinal studies are needed to elucidate whether these abnormalities presage disease onset or are consequences of disease processes, and to identify potential contributing factors. Here, we narratively review and summarize longitudinal structural magnetic resonance imaging studies that relate imaging outcomes to manic episodes. First, we conclude that longitudinal brain imaging studies suggest an association of bipolar disorder with aberrant brain changes, including both deviant decreases and increases in morphometric measures. Second, we conclude that manic episodes have been related to accelerated cortical volume and thickness decreases, with the most consistent findings occurring in prefrontal brain areas. Importantly, evidence also suggests that in contrast to healthy controls, who in general show age-related cortical decline, brain metrics remain stable or increase during euthymic periods in bipolar disorder patients, potentially reflecting structural recovering mechanisms. The findings stress the importance of preventing manic episodes. We further propose a model of prefrontal cortical trajectories in relation to the occurrence of manic episodes. Finally, we discuss potential mechanisms at play, remaining limitations, and future directions.

Atypical antipsychotic-induced mania: A systematic review and meta-analysis

BACKGROUND

The possibility of atypical antipsychotics (AA) to induce manic symptoms has been raised by several articles. The objective of this study was to describe whether exposure to AA may induce mania in mood disorders.

METHODS

We performed a systematic review following the preferred reporting items for systematic reviews and meta-analysis guidelines. The systematic search encompassed all relevant studies published until April 4th, 2022. A meta-analysis testing whether treatment emergent mania (TEM) is more frequent with the use of AA compared with placebo was performed.

RESULTS

A total of 52 studies were included in the systematic review. We found 24 case reports or case series describing 40 manic/hypomanic episodes allegedly induced by AA. Twenty-one placebo-controlled trials were included in a meta-analysis including 4823 individuals treated with AA and 3252 individuals receiving placebo. Our meta-analysis showed that the use of AA protects against the development of TEM (OR: 0.68 [95 % CI: 0.52-0.89], p = 0.005).

LIMITATIONS

AA-induced mania/hypomania was not the primary outcome in any of the observational or interventional studies. TEM was not homogeneously defined across studies. In most case reports it was not possible to establish causality between the use of AA and the development of manic symptoms.

CONCLUSIONS

TEM is more frequent with placebo than with AA, which suggests that AA exposure does not represent a relevant risk for TEM. Mania/hypomania induced by an AA seems to be rare events, since anecdotal evidence from case reports and case series were not observed in observational prospective and interventional studies.

The Brain Overwork Scale: A Population-Based Cross-Sectional Study on the Psychometric Properties of a New 10-Item Scale to Assess Mental Distress in Mongolia

Identifying mental distress is a complex task, particularly when individuals experience physical symptoms. Traditional self-report questionnaires that detect psychiatric symptoms using emotional words may not work for these individuals. Consequently, there is a need for a screening tool that can identify both the physical and mental symptoms of mental distress in individuals without a clinical diagnosis. Our study aimed to develop and validate a scale that measures mental distress by measuring the extent of brain overwork, which can be extrapolated as the burden of mental distress. In this population-based cross-sectional study, we recruited a total of 739 adults aged 16–65 years from 64 sampling centers of a cohort in Mongolia to validate a 10-item self-report questionnaire. Internal consistency was measured using McDonald’s ω coefficient. Test–retest reliability was analyzed using intraclass correlation coefficients. Construct and convergent validities were examined using principal component analysis (PCA) and confirmatory factor analysis (CFA). The Hospital Anxiety and Depression Scale (HADS) and the abbreviated version of World Health Organization Quality of Life (WHOQOL-BREF) were used to evaluate criterion validity. Among the participants, 70.9% were women, 22% held a bachelor’s degree or higher, 38.8% were employed, and 66% were married. The overall McDonald’s ω coefficient was 0.861, demonstrating evidence of excellent internal consistency. The total intraclass correlation coefficient of the test–retest analysis was 0.75, indicating moderate external reliability. PCA and CFA established a three-domain structure that provided an excellent fit to the data (RMSEA = 0.033, TLI = 0.984, CFI = 0.989, χ2 = 58, p = 0.003). This 10-item scale, the Brain Overwork Scale (BOS-10), determines mental distress in three dimensions: excessive thinking, hypersensitivity, and restless behavior. All the items had higher item-total correlations with their corresponding domain than they did with the other domains, and correlations between the domain scores had a range of 0.547–0.615. BOS-10 correlated with HADS, whereas it was inversely correlated with WHOQOL-BREF. In conclusion, the results suggest that BOS-10 is a valid and reliable instrument for assessing mental distress in the general population. The scale screens for mental distress that is characterized by subjective symptoms such as excessive thinking, hypersensitivity, and restless behavior. The current findings also demonstrate that the BOS-10 is quantitative, simple, and applicable for large group testing. This scale may be useful for identifying at-risk individuals who may require further evaluation and treatment for mental distress.

Cerebral perfusion is related to antidepressant effect and cognitive side effects of Electroconvulsive Therapy

BACKGROUND

The mechanisms underlying the antidepressant effect and cognitive side effects of Electroconvulsive Therapy (ECT) remain elusive. The measurement of cerebral perfusion provides an insight into brain physiology.

OBJECTIVE

We investigated ECT-related perfusion changes in depressed patients and tested whether these changes correlate with clinical effects.

METHODS

A sample of 22 in-patients was examined at three time points: 1) within two days before, 2) within one week after, and 3) six months after an ECT series. Cerebral perfusion was quantified using arterial spin labeling magnetic resonance imaging. The primary regions of interest were the bilateral dorsolateral prefrontal cortices (DL-PFC) and hippocampi. The depression severity was assessed by the six-item Hamilton Depression Rating Scale, and cognitive performance by the Screen for Cognitive Impairment in Psychiatry. A linear mixed model and partial correlation were used for statistical analyses.

RESULTS

Following an ECT series, perfusion decreased in the right (-6.0%, p = .01) and left DL-PFC (-5.6%, p = .001). Perfusion increased in the left hippocampus (4.8%, p = .03), while on the right side the increase was insignificant (2.3%, p = .23). A larger perfusion reduction in the right DL-PFC correlated with a better antidepressant effect, and a larger perfusion increase in the right hippocampus with worse cognitive impairment.

CONCLUSION

ECT-induced attenuation of prefrontal activity may be related to clinical improvement, whereas a hippocampal process triggered by the treatment is likely associated with cognitive side effects.

A critical evaluation of dynamical systems models of bipolar disorder

Bipolar disorder (BD) is a mood disorder involving recurring (hypo)manic and depressive episodes. The inherently temporal nature of BD has inspired its conceptualization using dynamical systems theory, which is a mathematical framework for understanding systems that evolve over time. In this paper, we provide a critical review of the dynamical systems models of BD. Owing to the heterogeneity of methodological and experimental designs in computational modeling, we designed a structured approach that parallels the appraisal of animal models by their face, predictive, and construct validity. This tool, the validity appraisal guide for computational models (VAG-CM), is not an absolute measure of validity, but rather a guide for a more objective appraisal of models in this review. We identified 26 studies published before November 18, 2021 that proposed generative dynamical systems models of time-varying signals in BD. Two raters independently applied the VAG-CM to the included studies, obtaining a mean Cohen's κ of 0.55 (95% CI [0.45, 0.64]) prior to establishing consensus ratings. Consensus VAG-CM ratings revealed three model/study clusters: data-driven models with face validity, theory-driven models with predictive validity, and theory-driven models lacking all forms of validity. We conclude that future modeling studies should employ a hybrid approach that first operationalizes BD features of interest using empirical data to achieve face validity, followed by explanations of those features using generative models with components that are homologous to physiological or psychological systems involved in BD, to achieve construct validity. Such models would be best developed alongside long-term prospective cohort studies involving a collection of multimodal time-series data. We also encourage future studies to extend, modify, and evaluate the VAG-CM approach for a wider breadth of computational modeling studies and psychiatric disorders.