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name: Bipolar Disorder
creation_date: '2025-12-18T17:01:35Z'
updated_date: '2026-02-17T21:53:14Z'
category: Complex
parents:
- Psychiatric Disease
disease_term:
preferred_term: bipolar disorder
term:
id: MONDO:0004985
label: bipolar disorder
has_subtypes:
- name: Bipolar I Disorder
description: Characterized by manic episodes, with or without depressive
episodes.
- name: Bipolar II Disorder
description: Characterized by hypomanic and depressive episodes, no full
mania.
- name: Cyclothymic Disorder
description: Chronic fluctuating mood with hypomanic and depressive symptoms.
pathophysiology:
- name: Monoamine Dysregulation
description: >
Imbalances in dopamine, norepinephrine, and serotonin neurotransmission
contribute to mood episodes. Elevated dopamine in mania, reduced in
depression.
cell_types:
- preferred_term: Dopaminergic Neuron
term:
id: CL:0000700
label: dopaminergic neuron
- preferred_term: Serotonergic Neuron
term:
id: CL:0000850
label: serotonergic neuron
- preferred_term: Noradrenergic Neuron
term:
id: CL:0008025
label: noradrenergic neuron
biological_processes:
- preferred_term: Neurotransmitter Signaling
term:
id: GO:0007268
label: chemical synaptic transmission
evidence:
- reference: PMID:22363263
reference_title: "Inhibition of GSK3 by lithium, from single molecules to signaling networks."
supports: PARTIAL
snippet: "Activation of the dopamine receptor 2 (D2R) has been shown to stimulate
the inactivation of Akt by PP2A (Beaulieu et al., 2005; Beaulieu and Gainetdinov,
2011), therefore providing a mechanism through which GPCR activation can inhibit
Akt in response to extracellular signals."
explanation: Dopamine D2 receptor signaling regulates the Akt/GSK3 pathway,
providing a molecular link between monoaminergic neurotransmission and
mood regulation in bipolar disorder.
- reference: PMID:22363263
reference_title: "Inhibition of GSK3 by lithium, from single molecules to signaling networks."
supports: PARTIAL
snippet: "This mechanism of D2R signaling appears to play important roles in the
regulation of locomotor behavior and sensory motor gating by dopamine (Beaulieu
et al., 2004; Emamian et al., 2004). It could also contribute to the therapeutic
and/or adverse effects of psychoactive drugs like amphetamines and antpsychotics
that act on dopamine neurotransmission"
explanation: The D2 receptor-mediated regulation of GSK3 activity through
beta-arrestin signaling is implicated in behavioral regulation relevant to
bipolar disorder and the mechanism of mood stabilizers and antipsychotics.
- name: Mitochondrial Dysfunction
description: >
Impaired cellular energy metabolism and oxidative stress affect
neuronal function. Mitochondrial abnormalities linked to mood
dysregulation.
biological_processes:
- preferred_term: Mitochondrial Function
term:
id: GO:0007005
label: mitochondrion organization
evidence:
- reference: PMID:30285728
reference_title: "The TRAX, DISC1, and GSK3 complex in mental disorders and therapeutic interventions."
supports: NO_EVIDENCE
snippet: "Psychiatric disorders (such as bipolar disorder, depression, and schizophrenia)
affect the lives of millions of individuals worldwide."
explanation: This review discusses the molecular mechanisms underlying
psychiatric disorders including bipolar disorder, with focus on the
DISC1/GSK3 complex which regulates mitochondrial and cellular functions.
- name: Circadian Rhythm Disruption
description: >
Disrupted sleep-wake cycles and circadian gene expression
contribute to mood instability. Sleep deprivation can trigger mania.
biological_processes:
- preferred_term: Circadian Rhythm
term:
id: GO:0007623
label: circadian rhythm
evidence:
- reference: PMID:22363263
reference_title: "Inhibition of GSK3 by lithium, from single molecules to signaling networks."
supports: NO_EVIDENCE
snippet: "For more than 60 years, the mood stabilizer lithium has been used alone
or in combination for the treatment of bipolar disorder, schizophrenia, depression,
and other mental illnesses."
explanation: This comprehensive review discusses lithium as the gold
standard treatment for bipolar disorder, noting its mood-stabilizing
effects through GSK3 inhibition which affects multiple cellular pathways
including circadian regulation.
- name: Neuroplasticity Alterations
description: >
Reduced BDNF and altered synaptic plasticity in mood circuits.
Lithium and other mood stabilizers enhance neuroplasticity.
cell_types:
- preferred_term: Neuron
term:
id: CL:0000540
label: neuron
biological_processes:
- preferred_term: Synaptic Plasticity
term:
id: GO:0048167
label: regulation of synaptic plasticity
evidence:
- reference: PMID:30285728
reference_title: "The TRAX, DISC1, and GSK3 complex in mental disorders and therapeutic interventions."
supports: PARTIAL
snippet: "DISC1 binds directly to GSK3 and modulates many cellular functions by
negatively inhibiting GSK3 activity."
explanation: GSK3 inhibition by DISC1 and mood stabilizers like lithium is a
key mechanism in bipolar disorder treatment, affecting synaptic plasticity
and neuronal survival pathways.
- reference: PMID:30285728
reference_title: "The TRAX, DISC1, and GSK3 complex in mental disorders and therapeutic interventions."
supports: PARTIAL
snippet: "In the present review, we will focus on the emerging roles of TRAX and
its interacting proteins (including DISC1 and GSK3β) in psychiatric disorders
and the potential implications for developing therapeutic interventions."
explanation: The TRAX/DISC1/GSK3β complex is implicated in psychiatric
disorders including bipolar disorder and represents a therapeutic target
for enhancing neuroplasticity.
- name: Neuroinflammation
description: >
Elevated inflammatory markers during mood episodes. Microglial
activation and cytokine abnormalities contribute to pathophysiology.
cell_types:
- preferred_term: Microglia
term:
id: CL:0000129
label: microglial cell
biological_processes:
- preferred_term: Inflammatory Response
term:
id: GO:0006954
label: inflammatory response
evidence:
- reference: PMID:33958577
reference_title: "Glutamate and microglia activation as a driver of dendritic apoptosis: a core pathophysiological mechanism to understand schizophrenia."
supports: NO_EVIDENCE
snippet: "considering that schizophrenia is a multifactorial and highly polygenic
disorder that shares many risk genes with other psychiatric illnesses including
bipolar disorder, depression, intellectual disability and autism spectrum disorders,
it is to be expected that these diseases may also share some of these same mechanisms"
explanation: Microglial activation and inflammatory processes are shared
pathophysiological mechanisms across psychiatric disorders including
bipolar disorder, contributing to synaptic dysfunction.
phenotypes:
- name: Manic Episodes
category: Psychiatric
frequency: VERY_FREQUENT
diagnostic: true
notes: Elevated mood, decreased sleep, increased activity
phenotype_term:
preferred_term: Mania
term:
id: HP:0100754
label: Mania
- name: Depressive Episodes
category: Psychiatric
frequency: VERY_FREQUENT
phenotype_term:
preferred_term: Depression
term:
id: HP:0000716
label: Depression
- name: Sleep Disturbance
category: Psychiatric
frequency: VERY_FREQUENT
notes: Decreased need for sleep in mania, insomnia or hypersomnia in
depression
phenotype_term:
preferred_term: Sleep Disturbance
term:
id: HP:0002360
label: Sleep disturbance
- name: Psychosis
category: Psychiatric
frequency: OCCASIONAL
notes: Can occur in severe mania or depression
phenotype_term:
preferred_term: Psychosis
term:
id: HP:0000709
label: Psychosis
- name: Anxiety
category: Psychiatric
frequency: FREQUENT
phenotype_term:
preferred_term: Anxiety
term:
id: HP:0000739
label: Anxiety
- name: Cognitive Impairment
category: Neurological
frequency: FREQUENT
notes: Executive function, attention deficits
phenotype_term:
preferred_term: Cognitive Impairment
term:
id: HP:0100543
label: Cognitive impairment
evidence:
- reference: PMID:23846857
reference_title: "Clinical phenotypes of psychosis in the Bipolar-Schizophrenia Network on Intermediate Phenotypes (B-SNIP)."
supports: PARTIAL
snippet: "All proband groups showed lower psychosocial functioning than the relatives
or comparison group. On average, schizophrenia probands showed more symptoms
and lower psychosocial functioning than probands with psychotic bipolar disorder,
but there was considerable overlap in clinical manifestations."
explanation: The B-SNIP study demonstrates that cognitive and psychosocial
impairment is a consistent feature across psychotic disorders including
bipolar disorder, though with varying severity.
biochemical:
- name: BDNF
presence: Decreased
context: Reduced in both manic and depressive episodes
- name: Cortisol
presence: Elevated
context: HPA axis dysregulation
- name: Inflammatory Markers
presence: Elevated
context: IL-6, TNF-alpha during episodes
genetic:
- name: CACNA1C
association: Risk Factor
notes: Calcium channel
evidence:
- reference: PMID:18711365
reference_title: "Collaborative genome-wide association analysis supports a role for ANK3 and CACNA1C in bipolar disorder."
supports: SUPPORT
snippet: "We also found further support for the previously reported CACNA1C (alpha
1C subunit of the L-type voltage-gated calcium channel; combined P = 7.0 x 10(-8),
rs1006737)."
explanation: Landmark GWAS study providing genome-wide significant evidence
that CACNA1C is a susceptibility locus for bipolar disorder, implicating
calcium channel dysfunction in disease pathogenesis.
- reference: PMID:21057379
reference_title: "Case-case genome-wide association analysis shows markers differentially associated with schizophrenia and bipolar disorder and implicates calcium channel genes."
supports: SUPPORT
snippet: "The finding for CACNG5, taken together with the earlier implication
of CACNA1C and CACNA1B, strongly suggests a key role for voltage-dependent calcium
channel genes in the susceptibility to bipolar disorder and/or schizophrenia."
explanation: Case-case GWAS analysis further confirms the critical role of
calcium channel genes including CACNA1C in bipolar disorder
susceptibility.
- name: ANK3
association: Risk Factor
notes: Ankyrin-3
evidence:
- reference: PMID:18711365
reference_title: "Collaborative genome-wide association analysis supports a role for ANK3 and CACNA1C in bipolar disorder."
supports: SUPPORT
snippet: "To identify susceptibility loci for bipolar disorder, we tested 1.8
million variants in 4,387 cases and 6,209 controls and identified a region of
strong association (rs10994336, P = 9.1 x 10(-9)) in ANK3 (ankyrin G)."
explanation: Genome-wide significant association of ANK3 with bipolar
disorder in large-scale GWAS, establishing ankyrin G as a key
susceptibility gene that may affect neuronal excitability and synaptic
function.
- name: ODZ4
association: Risk Factor
- name: NCAN
association: Risk Factor
environmental:
- name: Childhood Trauma
notes: Increases risk
- name: Sleep Deprivation
notes: Can trigger manic episodes
- name: Substance Use
notes: Comorbid and can trigger episodes
- name: Stress
notes: Life events can precipitate episodes
treatments:
- name: Lithium
description: First-line mood stabilizer, effective for mania and suicide
prevention.
evidence:
- reference: PMID:22363263
reference_title: "Inhibition of GSK3 by lithium, from single molecules to signaling networks."
supports: SUPPORT
snippet: "Lithium has been reported to reduce suicide rates and prevent manic
episodes in individuals with bipolar disorder, major depression, or schizoaffective
disorders"
explanation: Lithium is the gold standard mood stabilizer for bipolar
disorder with demonstrated efficacy in preventing manic episodes and
reducing suicide risk through GSK3 inhibition.
- reference: PMID:22363263
reference_title: "Inhibition of GSK3 by lithium, from single molecules to signaling networks."
supports: SUPPORT
snippet: "In 1996, two independent studies (Klein and Melton, 1996; Stambolic
et al., 1996) of the effects of lithium on cell signaling and development have
identified a direct effect of lithium on the activity of GSK3 both in vitro
and in cells."
explanation: Lithium's therapeutic mechanism involves direct inhibition of
GSK3 and indirect effects through the Akt/beta-arrestin pathway, providing
molecular basis for its mood-stabilizing effects.
- name: Valproate
description: Mood stabilizer, effective for mania.
- name: Lamotrigine
description: Mood stabilizer, more effective for depression prevention.
- name: Atypical Antipsychotics
description: Quetiapine, olanzapine, aripiprazole for mania and maintenance.
- name: Antidepressants
description: Used cautiously with mood stabilizer to prevent switch to mania.
- name: Psychotherapy
description: CBT, interpersonal therapy, psychoeducation.
- name: ECT
description: For severe or treatment-resistant episodes.
classifications:
harrisons_chapter:
- classification_value: psychiatric disorder
datasets:
references:
- reference: DOI:10.1503/jpn.230112
title: Advances in the understanding of the pathophysiology of schizophrenia
and bipolar disorder through induced pluripotent stem cell models
findings: []
- reference: DOI:10.3389/fnins.2023.1228455
title: Non-canonical pathways in the pathophysiology and therapeutics of
bipolar disorder
findings: []
- reference: DOI:10.3389/fpsyt.2024.1414776
title: 'The genetic association between bipolar disorder and dementia: a qualitative
review'
findings: []
- reference: DOI:10.3390/biology13100787
title: 'Codes between Poles: Linking Transcriptomic Insights into the Neurobiology
of Bipolar Disorder'
findings: []
- reference: DOI:10.3390/brainsci14121199
title: 'Mitochondrial Dysfunction as a Biomarker of Illness State in Bipolar Disorder:
A Critical Review'
findings: []
Disease Pathophysiology Research Report
Target Disease - Disease Name: Bipolar Disorder - MONDO ID: MONDO_0004985 - Category: Complex
Pathophysiology description (current understanding, 2023–2024 priority) Bipolar disorder (BD) is a polygenic, neurodevelopmentally rooted disorder characterized by recurrent episodes of mania/hypomania and depression with persistent cognitive and functional burden. Convergent molecular evidence implicates dysregulation across: (i) calcium/ion channel signaling and synaptic machinery; (ii) glutamate–GABA and monoaminergic neurotransmission; (iii) immune–inflammatory cascades; (iv) mitochondrial bioenergetics and redox homeostasis; (v) circadian clock mechanisms and neurotrophic/synaptic plasticity pathways; and (vi) oligodendroglial/myelin processes impacting fronto-limbic circuits. Notably, multiple recent syntheses underscore cross-talk between these domains, providing a mechanistic basis for mood state switching, neuroprogression, and cognitive impairment (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (machadovieira2023noncanonicalpathwaysin pages 3-5).
Directly quoted evidence highlights mitochondrial and inflammatory abnormalities and their interplay with synaptic/circadian pathways in BD: “a larger number of smaller-sized mitochondria have been found,” with “downregulation of fusion proteins (Mfn-2, Opa-1) and upregulation of fission (Fis-1), impaired mitophagy, higher cell-free mtDNA,” and a pro-inflammatory milieu (IL-1β, IL-6, TNF-α), alongside “greater activation [of] GSK-3α/β” and “upregulated” PI3K/Akt–mTOR in mania (Nov 2024; https://doi.org/10.3390/brainsci14121199) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). Transcriptomic integration studies emphasize synaptic vesicle release/SNARE complex perturbation, regional specificity (DLPFC, nucleus accumbens, anterior cingulate), and links to insulin/energy pathways (Sep 2024; https://doi.org/10.3390/biology13100787) (garcia2024codesbetweenpoles pages 12-13, garcia2024codesbetweenpoles pages 16-17, garcia2024codesbetweenpoles pages 17-19). iPSC-based reviews report “disturbances in neurodevelopmental processes, imbalance in glutamatergic–GABAergic transmission and neuromorphological alterations” (Mar 2024; https://doi.org/10.1503/jpn.230112) (perrottelli2024advancesinthe pages 1-2). Clinically, BD associates with increased dementia risk and overlapping risk genes with neurodegeneration, including CACNA1C and SCN2A; meta-analytic estimates show approximately 2–3-fold higher dementia odds in BD (published Aug 20, 2024; https://doi.org/10.3389/fpsyt.2024.1414776) (hirakawa2024thegeneticassociation pages 1-2).
1) Core Pathophysiology - Primary mechanisms - Calcium/ion channel and synaptic signaling: GWAS convergently implicate CACNA1C (L-type Ca2+ channel) and other synaptic/ion channels (e.g., SCN2A) in BD liability; transcriptomics indicate dysregulation of SNARE-mediated synaptic vesicle exocytosis and kinase/phosphoinositide pathways in prefrontal systems (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455; Sep 2024; https://doi.org/10.3390/biology13100787) (machadovieira2023noncanonicalpathwaysin pages 3-5, garcia2024codesbetweenpoles pages 12-13, garcia2024codesbetweenpoles pages 16-17). - Neurotransmission: Evidence supports altered glutamate–GABA balance and monoaminergic systems; iPSC models show GABA–glutamate imbalance and neuromorphological changes; DRD2- and glutamate-related transcriptomic signals are regionally enriched (Mar 2024; https://doi.org/10.1503/jpn.230112; Sep 2024; https://doi.org/10.3390/biology13100787) (perrottelli2024advancesinthe pages 1-2, garcia2024codesbetweenpoles pages 16-17, garcia2024codesbetweenpoles pages 17-19). - Neuroinflammation: Pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) and inflammasome signaling (e.g., NLRP3) are repeatedly implicated; anti-inflammatory trials yield mixed results, underscoring heterogeneity and the need for biomarker stratification (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455; Nov 2024; https://doi.org/10.3390/brainsci14121199) (machadovieira2023noncanonicalpathwaysin pages 3-5, gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). - Mitochondria, bioenergetics, oxidative stress: Structural/functional mitochondrial abnormalities, impaired mitophagy, and oxidative stress markers are repeatedly observed; PI3K/Akt–mTOR and GSK3 signaling show state-related modulation (Nov 2024; https://doi.org/10.3390/brainsci14121199) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). - Circadian dysregulation: Clock gene variation and interplay with mitochondrial biogenesis/oxidative stress are noted; circadian mechanisms modulate neuronal survival and treatment response in cellular models (Nov 2024; https://doi.org/10.3390/brainsci14121199) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). - Oligodendrocyte/myelination: Clinical/imaging syntheses point to white/gray matter injury and myelin-related changes as part of neuroprogression, linked to cognitive deficits (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (machadovieira2023noncanonicalpathwaysin pages 3-5).
Calcium signaling and ion channel homeostasis (CACNA1C/SCN2A); Wnt/β-catenin, GSK3, PKC; PI3K/Akt–mTOR; inflammatory cytokine cascades and NLRP3; mitophagy/mitochondrial dynamics (Mfn-2/Opa1/Fis1, LC3); synaptic vesicle exocytosis/SNARE complex; insulin/IGF signaling in cortex (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455; Nov 2024; https://doi.org/10.3390/brainsci14121199; Sep 2024; https://doi.org/10.3390/biology13100787) (machadovieira2023noncanonicalpathwaysin pages 3-5, gimenezpalomo2024mitochondrialdysfunctionas pages 8-10, garcia2024codesbetweenpoles pages 12-13, garcia2024codesbetweenpoles pages 16-17, garcia2024codesbetweenpoles pages 17-19).
Affected cellular processes
2) Key Molecular Players - Genes/Proteins (HGNC) - CACNA1C (L-type CaV1.2 alpha-1 subunit): BD risk and neuropsychiatric pleiotropy; overlaps with dementia risk; calcium signaling–synaptic plasticity (Aug 2024; https://doi.org/10.3389/fpsyt.2024.1414776) (hirakawa2024thegeneticassociation pages 1-2). - SCN2A (Nav1.2): BD–dementia overlap; neuronal excitability (Aug 2024; https://doi.org/10.3389/fpsyt.2024.1414776) (hirakawa2024thegeneticassociation pages 1-2). - ANK3 (ankyrin-G): GWAS-implicated scaffold at AIS/nodes; synaptic/circuit stability (Nov 2024; https://doi.org/10.3390/brainsci14121199) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). - GSK3B (GSK3β): Increased activation in mania; ties to Wnt/β-catenin and mood stabilizer targets (Nov 2024; https://doi.org/10.3390/brainsci14121199; Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10, machadovieira2023noncanonicalpathwaysin pages 3-5). - DRD2 (dopamine D2 receptor): Transcriptomic and regional associations (nucleus accumbens); monoaminergic dysregulation (Sep 2024; https://doi.org/10.3390/biology13100787) (garcia2024codesbetweenpoles pages 12-13). - BDNF (brain-derived neurotrophic factor): Neuroplasticity/synaptic remodeling implicated by systems reviews; interacts with dopaminergic and glutamatergic mechanisms (Sep 2024; https://doi.org/10.3390/biology13100787; Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (garcia2024codesbetweenpoles pages 17-19, machadovieira2023noncanonicalpathwaysin pages 3-5). - Mitophagy/mitochondrial dynamics proteins: OPA1, MFN2, FIS1; LC3; apoptosis regulators (BCL2↓, FAS/BAK/APAF1↑) (Nov 2024; https://doi.org/10.3390/brainsci14121199) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10).
Dopamine (CHEBI:18243) and serotonin/5-HT (CHEBI:28790): DRD2, serotonergic receptors (regional/network effects) (Sep 2024; https://doi.org/10.3390/biology13100787) (garcia2024codesbetweenpoles pages 12-13, garcia2024codesbetweenpoles pages 16-17).
Cell types (CL)
Oligodendrocyte (CL:0000128): myelin integrity; white matter connectivity (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (machadovieira2023noncanonicalpathwaysin pages 3-5).
Anatomical locations (UBERON)
3) Biological Processes (GO) disrupted - Synaptic vesicle exocytosis and regulation of neurotransmitter secretion; long-term synaptic plasticity (GO:0016079, GO:0099177, GO:0048167) supported by SNARE-complex and neurotrophin/mTOR signaling changes (Sep 2024; https://doi.org/10.3390/biology13100787; Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (garcia2024codesbetweenpoles pages 12-13, machadovieira2023noncanonicalpathwaysin pages 3-5). - Regulation of membrane potential and calcium ion transmembrane transport (GO:0042391, GO:0070588) via CACNA1C/SCN2A dysregulation (Aug 2024; https://doi.org/10.3389/fpsyt.2024.1414776) (hirakawa2024thegeneticassociation pages 1-2). - Inflammatory response and cytokine-mediated signaling (GO:0006954; GO:0019221) including NLRP3–IL-1β/IL-18 axis (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (machadovieira2023noncanonicalpathwaysin pages 3-5). - Mitochondrial organization, mitophagy, oxidative phosphorylation, and response to oxidative stress (GO:0007005; GO:0000422; GO:0006119; GO:0006979) (Nov 2024; https://doi.org/10.3390/brainsci14121199) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). - Circadian rhythm and clock gene transcription feedback loops (GO:0007623; GO:0006342 related to chromatin/cycle regulation) linking to survival pathways (Nov 2024; https://doi.org/10.3390/brainsci14121199) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). - Myelination and axon ensheathment (GO:0042552; GO:0008366) with white matter connectivity consequences (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (machadovieira2023noncanonicalpathwaysin pages 3-5).
4) Cellular Components (GO) - Synapse, presynaptic active zone, postsynaptic density (GO:0045202; GO:0048786; GO:0014069) (Sep 2024; https://doi.org/10.3390/biology13100787) (garcia2024codesbetweenpoles pages 12-13). - Mitochondrion, mitochondrial inner membrane, mitophagosome (GO:0005739; GO:0005743; GO:0000422) (Nov 2024; https://doi.org/10.3390/brainsci14121199) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). - Node of Ranvier/axon initial segment (ANK3 scaffolding), myelin sheath (GO:0030674; GO:0043209) (Nov 2024; https://doi.org/10.3390/brainsci14121199; Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10, machadovieira2023noncanonicalpathwaysin pages 3-5).
5) Disease Progression - Sequence of events (hypothesis-driven): 1) Genetic predisposition (polygenic risk in calcium/ion channels and synaptic genes) and developmental perturbations alter early neural circuit maturation (Aug 2024; https://doi.org/10.3389/fpsyt.2024.1414776; Mar 2024; https://doi.org/10.1503/jpn.230112) (hirakawa2024thegeneticassociation pages 1-2, perrottelli2024advancesinthe pages 1-2). 2) Vulnerable circuits (fronto-limbic–striatal and cerebellar contributions) exhibit E/I imbalance and synaptic plasticity deficits under stressors (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455; Sep 2024; https://doi.org/10.3390/biology13100787) (machadovieira2023noncanonicalpathwaysin pages 3-5, garcia2024codesbetweenpoles pages 16-17). 3) Bioenergetic strain and oxidative stress with impaired mitophagy lead to “smaller-sized mitochondria,” apoptotic signaling, and inflammatory amplification (Nov 2024; https://doi.org/10.3390/brainsci14121199) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). 4) Myelin/white-matter injury and synaptic dysfunction contribute to neuroprogression and cognitive decline, with epidemiologic links to later-life dementia risk (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455; Aug 2024; https://doi.org/10.3389/fpsyt.2024.1414776) (machadovieira2023noncanonicalpathwaysin pages 3-5, hirakawa2024thegeneticassociation pages 1-2).
6) Phenotypic manifestations and mechanistic links - Core clinical phenotypes (HP terms): mania (HP:0000718), depression (HP:0000716), sleep/circadian disturbance (HP:0002360), cognitive impairment (HP:0100543). Mechanistically, E/I imbalance and synaptic plasticity failure in DLPFC–ACC–limbic networks relate to affective lability and executive/memory deficits. The increased dementia risk in BD (OR ~2.36–2.96) supports neuroprogressive processes bridging mitochondrial, inflammatory, and synaptic/myelin pathology (published Aug 20, 2024; https://doi.org/10.3389/fpsyt.2024.1414776) (hirakawa2024thegeneticassociation pages 1-2), consistent with white/gray matter involvement and inflammatory–kynurenine axes (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (machadovieira2023noncanonicalpathwaysin pages 3-5).
Recent developments and latest research (2023–2024 priority) - Non-canonical pathways integrating immune–mitochondrial–synaptic axes, with mixed but instructive anti-inflammatory RCT signals; emphasis on NLRP3, lipid–eicosanoid signaling, and microbiome–immune interventions (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (machadovieira2023noncanonicalpathwaysin pages 3-5). - Mitochondrial dynamics/mitophagy and mood-state signaling (GSK3, PI3K/Akt–mTOR) refined as episode-linked biomarkers; circadian–mitochondrial cross-talk proposed (Nov 2024; https://doi.org/10.3390/brainsci14121199) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). - Transcriptomic regionalization: DLPFC (synaptic/insulin pathways), ACC and nAcc (glutamate/dopamine genes) with SNARE complex involvement; lithium-related hippocampal plasticity (Sep 2024; https://doi.org/10.3390/biology13100787) (garcia2024codesbetweenpoles pages 12-13, garcia2024codesbetweenpoles pages 16-17, garcia2024codesbetweenpoles pages 17-19). - iPSC models extend causal inference on neurodevelopmental deficits and E/I imbalance in BD and schizophrenia spectra (Mar 2024; https://doi.org/10.1503/jpn.230112) (perrottelli2024advancesinthe pages 1-2). - Genetic cross-disorder overlap with dementia, highlighting CACNA1C and SCN2A in BD neuroprogression and cognitive risk trajectories (Aug 2024; https://doi.org/10.3389/fpsyt.2024.1414776) (hirakawa2024thegeneticassociation pages 1-2).
Current applications and real-world implementations - Mood stabilizers (e.g., lithium) and atypical antipsychotics act partly via neuroplasticity/PKC–GSK3 and synaptic signaling; lithium-associated hippocampal volume maintenance aligns with neurotrophic hypotheses (Sep 2024; https://doi.org/10.3390/biology13100787; Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (garcia2024codesbetweenpoles pages 17-19, machadovieira2023noncanonicalpathwaysin pages 3-5). - Anti-inflammatory strategies (minocycline, infliximab) show mixed efficacy overall but signal in biomarker-defined subgroups (e.g., childhood maltreatment), motivating stratified trials (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (machadovieira2023noncanonicalpathwaysin pages 3-5). - Translational disease modeling with iPSCs/organoids enables patient-specific interrogation of synaptic, mitochondrial, and developmental phenotypes for target discovery (Mar 2024; https://doi.org/10.1503/jpn.230112) (perrottelli2024advancesinthe pages 1-2).
Expert opinions and analysis from authoritative sources - Frontiers in Neuroscience (Aug 2023) authors argue BD is best conceptualized as a systems disorder with “immune-inflammatory mechanisms,” mitochondrial threshold effects (bioenergetics/ROS/Ca2+), and synaptic/myelin consequences, requiring multimodal treatment development (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (machadovieira2023noncanonicalpathwaysin pages 3-5). - Brain Sciences (Nov 2024) review synthesizes a mechanistic cascade from mitochondrial dynamics and impaired mitophagy to apoptosis and inflammatory amplification, linking to episode-specific kinase signaling (GSK3, mTOR) and circadian–mitochondrial coupling (Nov 2024; https://doi.org/10.3390/brainsci14121199) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). - J Psychiatry & Neuroscience (Mar 2024) highlights iPSC evidence for glutamate–GABA imbalance and neurodevelopmental disruptions as convergent features across BD and schizophrenia spectrum (Mar 2024; https://doi.org/10.1503/jpn.230112) (perrottelli2024advancesinthe pages 1-2).
Relevant statistics and data from recent studies - Dementia risk: Two meta-analytic estimates cited in an Aug 2024 review reported increased dementia odds in BD of OR 2.36 (95% CI 1.36–4.09) and OR 2.96 (95% CI 2.09–4.18) (Aug 20, 2024; https://doi.org/10.3389/fpsyt.2024.1414776) (hirakawa2024thegeneticassociation pages 1-2). - Mitochondrial morphology/dynamics: “larger number of smaller-sized mitochondria” with fusion (Mfn-2/Opa-1) down and fission (Fis-1) up; increased cell-free mtDNA; mitophagy/apoptosis markers altered (Nov 2024; https://doi.org/10.3390/brainsci14121199) (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). - Anti-inflammatory RCTs: minocycline positive in some, null in factorial designs; infliximab ineffective overall but signals in maltreatment subgroup; meta-analyses suggest insufficient evidence for routine NSAIDs/omega-3/pioglitazone, limited single-study support for NAC (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (machadovieira2023noncanonicalpathwaysin pages 3-5).
Ontology-anchored annotations (selected examples) - Genes/Proteins (HGNC): CACNA1C; SCN2A; ANK3; GSK3B; DRD2; BDNF (hirakawa2024thegeneticassociation pages 1-2, gimenezpalomo2024mitochondrialdysfunctionas pages 8-10, machadovieira2023noncanonicalpathwaysin pages 3-5, garcia2024codesbetweenpoles pages 12-13, garcia2024codesbetweenpoles pages 17-19). - Biological Processes (GO): synaptic vesicle exocytosis; regulation of calcium transport; cytokine-mediated signaling; mitophagy; oxidative phosphorylation; circadian rhythm; myelination (garcia2024codesbetweenpoles pages 12-13, machadovieira2023noncanonicalpathwaysin pages 3-5, gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). - Cellular Components (GO): synapse/PSD; mitochondrion/inner membrane; mitophagosome; myelin sheath; node of Ranvier/AIS (garcia2024codesbetweenpoles pages 12-13, gimenezpalomo2024mitochondrialdysfunctionas pages 8-10, machadovieira2023noncanonicalpathwaysin pages 3-5). - Cell types (CL): neuron; microglia; astrocyte; oligodendrocyte (perrottelli2024advancesinthe pages 1-2, machadovieira2023noncanonicalpathwaysin pages 3-5). - Anatomical Locations (UBERON): DLPFC; ACC; nucleus accumbens; hippocampus (garcia2024codesbetweenpoles pages 12-13, garcia2024codesbetweenpoles pages 16-17, garcia2024codesbetweenpoles pages 17-19). - Chemical entities (CHEBI): glutamate; GABA; dopamine; serotonin (perrottelli2024advancesinthe pages 1-2, garcia2024codesbetweenpoles pages 12-13). - Phenotypes (HP): mania; depressive episode; cognitive impairment; sleep disturbance (hirakawa2024thegeneticassociation pages 1-2, machadovieira2023noncanonicalpathwaysin pages 3-5).
Evidence Items (selected, with URLs and dates) - Machado-Vieira et al. “Non-canonical pathways in the pathophysiology and therapeutics of bipolar disorder.” Frontiers in Neuroscience. Published Aug 2023. URL: https://doi.org/10.3389/fnins.2023.1228455 (machadovieira2023noncanonicalpathwaysin pages 3-5). - Giménez-Palomo et al. “Mitochondrial Dysfunction as a Biomarker of Illness State in Bipolar Disorder: A Critical Review.” Brain Sciences. Nov 2024. URL: https://doi.org/10.3390/brainsci14121199 (gimenezpalomo2024mitochondrialdysfunctionas pages 8-10). - Perrottelli et al. “Advances in the understanding of the pathophysiology of schizophrenia and bipolar disorder through iPSC models.” J Psychiatry & Neuroscience. Mar 2024. URL: https://doi.org/10.1503/jpn.230112 (perrottelli2024advancesinthe pages 1-2). - Garcia & Tayo. “Codes between Poles: Transcriptomic Insights…” Biology. Sep 2024. URL: https://doi.org/10.3390/biology13100787 (garcia2024codesbetweenpoles pages 16-17, garcia2024codesbetweenpoles pages 12-13, garcia2024codesbetweenpoles pages 17-19). - Hirakawa & Terao. “The genetic association between bipolar disorder and dementia.” Frontiers in Psychiatry. Aug 20, 2024. URL: https://doi.org/10.3389/fpsyt.2024.1414776 (hirakawa2024thegeneticassociation pages 1-2).
Notes and limitations - Many mechanistic domains show heterogeneity across studies. Anti-inflammatory interventions require biomarker-guided stratification; mitochondrial/synaptic markers vary by episode/state. iPSC studies, while highly informative, require standardization and deeper phenotypic anchoring (Mar 2024; https://doi.org/10.1503/jpn.230112; Aug 2023; https://doi.org/10.3389/fnins.2023.1228455) (perrottelli2024advancesinthe pages 1-2, machadovieira2023noncanonicalpathwaysin pages 3-5).
Summary BD pathophysiology reflects convergent dysregulation of calcium/ion channel–synaptic systems, glutamate–GABA and monoamines, immune–inflammatory cascades, mitochondrial/oxidative pathways, and circadian and neurotrophic plasticity, with oligodendroglial/myelin changes impairing fronto-limbic networks. State-associated kinase signaling (GSK3, PI3K/Akt–mTOR), impaired mitophagy/oxidative stress, and cytokine activation provide plausible mechanisms for mood switches and neuroprogression with measurable cognitive risk. This multi-axis model is supported by 2023–2024 evidence from genetics, transcriptomics, mitochondria-focused reviews, and iPSC studies and motivates biomarker-stratified, circuit- and pathway-targeted therapeutics (Aug 2023; https://doi.org/10.3389/fnins.2023.1228455; Nov 2024; https://doi.org/10.3390/brainsci14121199; Mar 2024; https://doi.org/10.1503/jpn.230112; Aug 2024; https://doi.org/10.3389/fpsyt.2024.1414776) (machadovieira2023noncanonicalpathwaysin pages 3-5, gimenezpalomo2024mitochondrialdysfunctionas pages 8-10, perrottelli2024advancesinthe pages 1-2, hirakawa2024thegeneticassociation pages 1-2).
References
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(gimenezpalomo2024mitochondrialdysfunctionas pages 8-10): Anna Giménez-Palomo, Helena Andreu, Oscar de Juan, Luis Olivier, Iñaki Ochandiano, Lidia Ilzarbe, Marc Valentí, Aldo Stoppa, Cristian-Daniel Llach, Giulio Pacenza, Ana Cristina Andreazza, Michael Berk, Eduard Vieta, and Isabella Pacchiarotti. Mitochondrial dysfunction as a biomarker of illness state in bipolar disorder: a critical review. Brain Sciences, 14:1199, Nov 2024. URL: https://doi.org/10.3390/brainsci14121199, doi:10.3390/brainsci14121199. This article has 13 citations and is from a poor quality or predatory journal.
(garcia2024codesbetweenpoles pages 12-13): Jon Patrick T. Garcia and Lemmuel L. Tayo. Codes between poles: linking transcriptomic insights into the neurobiology of bipolar disorder. Biology, 13:787, Sep 2024. URL: https://doi.org/10.3390/biology13100787, doi:10.3390/biology13100787. This article has 4 citations and is from a poor quality or predatory journal.
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(hirakawa2024thegeneticassociation pages 1-2): Hirofumi Hirakawa and Takeshi Terao. The genetic association between bipolar disorder and dementia: a qualitative review. Frontiers in Psychiatry, Aug 2024. URL: https://doi.org/10.3389/fpsyt.2024.1414776, doi:10.3389/fpsyt.2024.1414776. This article has 1 citations and is from a poor quality or predatory journal.