Precision Dysregulation Across Hierarchical Predictive Systems: An Evolutionary–Existential Integration of Schizophrenia and Bipolar Spectrum Disorders 脳内世界モデル-10


Precision Dysregulation Across Hierarchical Predictive Systems:

An Evolutionary–Existential Integration of Schizophrenia and Bipolar Spectrum Disorders

Abstract

This paper proposes an integrative theoretical framework unifying evolutionary epistemology, predictive processing theory, dopamine-mediated precision encoding, and existential psychiatry. We conceptualize psychosis and bipolar spectrum disorders as disorders of hierarchical precision regulation within predictive systems. Schizophrenia is characterized as maladaptive hyper-precision of lower-level prediction errors coupled with instability of higher-order generative models, leading to fragmentation of information structure and delusion formation. Mania is modeled as pathological over-allocation of precision to exploratory priors (runaway exploration mode), whereas depression is reconceptualized as excessive fixation of prediction errors (error entrenchment). Schizoaffective conditions are interpreted as cross-hierarchical dysregulation. We further integrate the “manic-first hypothesis” within a developmental precision-instability framework. Clinical implications for cognitive-behavioral therapy and existential psychotherapy are elaborated. Two detailed case formulations illustrate the model’s explanatory and therapeutic utility.


1. Introduction

Why does the human brain successfully grasp the structure of the world?
Evolutionary epistemology suggests that cognition evolved not to discover absolute truth, but to generate models sufficiently adaptive for survival.

Contemporary predictive processing theory (Friston, Clark) conceptualizes the brain as a hierarchical generative model minimizing prediction error via Bayesian inference. However, psychopathology remains incompletely integrated into this framework.

We propose that major psychiatric syndromes can be reconceptualized as disorders of precision allocation across hierarchical levels of predictive processing.


2. Evolutionary Epistemology and Precision Allocation

Evolution does not optimize for truth but for adaptive fit. Organisms must balance:

  • Stability (model persistence)
  • Flexibility (model updating)

This balance is mathematically regulated by precision weighting — the confidence assigned to priors versus sensory prediction errors.

From an evolutionary perspective:

  • Excessive flexibility → instability
  • Excessive rigidity → maladaptation
  • Optimal cognition = dynamic precision regulation

Psychiatric disorders represent systematic breakdowns of this regulation.


3. Schizophrenia as Hierarchical Information Structural Collapse

3.1 Core Hypothesis

Schizophrenia involves:

  1. Hyper-precision of lower-level prediction errors
  2. Destabilization of higher-level priors
  3. Failure of hierarchical integration

This produces aberrant salience, fragmentation of meaning, and compensatory delusion formation.

Delusion is not random irrationality but an emergency attempt to restore global coherence within a destabilized generative hierarchy.

3.2 Information Structural Collapse

We define psychosis as:

A breakdown of cross-level informational coherence in hierarchical predictive systems.

The subject experiences:

  • Perceptual anomalies (micro-level instability)
  • Hyper-significance of trivial stimuli
  • Compensatory narrative construction (macro-level re-stabilization)

4. Bipolar Spectrum as Precision Oscillation Disorder

4.1 Mania: Runaway Exploration Mode

Mania is conceptualized as excessive precision assigned to high-level exploratory priors.

Formally:

  • Prior precision ↑↑
  • Sensory constraint ↓
  • Model updating biased toward novelty seeking

Clinically:

  • Grandiosity
  • Reduced need for sleep
  • Risk-taking
  • Rapid associative thinking

Mania represents evolutionary exploration mode without regulatory constraint.

4.2 Depression: Error Entrenchment

Depression is reconceptualized as excessive fixation of prediction errors.

  • Prediction error precision ↑
  • Prior flexibility ↓
  • Negative self-model rigidified

Result:

  • Hopelessness
  • Learned helplessness
  • Reduced behavioral exploration

4.3 Continuous Precision Fluctuation Model

We propose bipolar spectrum as a continuous oscillatory instability in precision allocation across hierarchical levels.


5. Schizoaffective Disorder as Cross-Hierarchical Dysregulation

Schizoaffective presentations involve:

  • Lower-level hyper-precision (psychotic features)
  • Higher-level oscillatory instability (mood dysregulation)

This explains phenomenological overlap without requiring categorical separation.


6. Dopamine as Neural Implementation of Precision Encoding

Empirical work suggests dopamine encodes precision of prediction errors.

  • Elevated striatal dopamine → increased salience attribution
  • Mania → dopaminergic overdrive in exploratory circuits
  • Psychosis → aberrant salience assignment
  • Depression → altered dopaminergic prediction error signaling

Thus dopamine functions as a biological gain-control mechanism for hierarchical inference.


7. Integration with the Manic-First Hypothesis

The manic-first hypothesis proposes that bipolar disorder may originate in manic dysregulation.

Within our framework:

Early instability in exploratory precision regulation
→ neurodevelopmental vulnerability
→ later compensatory depressive stabilization
→ oscillatory system organization


8. Existential Psychiatry and Predictive Processing

Predictive models are not merely computational; they structure meaning.

When hierarchical coherence collapses:

  • The self-model destabilizes.
  • World-model coherence dissolves.
  • Existential anxiety intensifies.

Psychosis may represent an existential emergency attempt at restoring meaning.

Depression may represent collapse of future-oriented predictive projection.

Thus predictive processing and existential psychiatry converge at the level of self-world modeling.


9. Clinical Case 1: Schizophrenia

Patient A (28-year-old male)

Symptoms:

  • Auditory hallucinations
  • Referential delusions
  • Social withdrawal

Formulation:

  • Hyper-precision of auditory prediction errors
  • Failure of top-down contextual priors
  • Compensatory delusional narrative (“surveillance system”)

Treatment:

  • Antipsychotic (dopamine modulation)
  • CBT: gradual re-weighting of alternative interpretations
  • Existential therapy: restoring narrative coherence

Outcome:
Improved hierarchical integration; delusion rigidity decreased.


10. Clinical Case 2: Bipolar I Disorder

Patient B (35-year-old female)

Manic phase:

  • Decreased sleep
  • Grand business plans
  • Increased spending

Formulation:

  • Over-precision of exploratory priors
  • Reduced sensory constraint
  • Accelerated generative model updating

Depressive phase:

  • Rumination
  • Self-blame
  • Behavioral inhibition

Treatment:

  • Mood stabilizer
  • Behavioral activation (controlled exploration)
  • CBT targeting precision misallocation

Outcome:
Reduced oscillation amplitude.


11. Clinical Implications

11.1 CBT Reformulation

CBT can be reconceptualized as guided precision recalibration:

  • Testing priors
  • Modulating error weighting
  • Restoring hierarchical coherence

11.2 Existential Therapy

  • Stabilizing self-model
  • Reconstructing meaning hierarchies
  • Supporting adaptive uncertainty tolerance

12. Discussion

This model integrates:

  • Evolutionary epistemology
  • Predictive processing
  • Dopaminergic precision encoding
  • Bipolar and psychotic phenomenology
  • Existential psychiatry

It avoids reductionism by recognizing:

  • Biological implementation
  • Computational structure
  • Phenomenological meaning

Psychiatric disorders become disorders of adaptive inference rather than categorical brain diseases.


13. Limitations and Future Directions

  • Empirical validation required
  • Neuroimaging precision metrics needed
  • Longitudinal oscillation modeling required
  • Cross-cultural existential modulation research

14. Conclusion

Psychosis and bipolar spectrum disorders can be reconceptualized as hierarchical precision dysregulation within evolutionary predictive systems.

Delusion is compensatory coherence construction.
Mania is runaway exploration.
Depression is error fixation.

Psychiatry, thus, becomes the science of restoring adaptive precision balance in meaning-generating organisms.


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