An interpretable TimeMIL framework for fNIRS: differential diagnosis between schizophrenia and bipolar disorder - Report - MDSpire

An interpretable TimeMIL framework for fNIRS: differential diagnosis between schizophrenia and bipolar disorder

  • By

  • Zefeng Wang

  • Binbin Gong

  • Lan Mou

  • Qian Tan

  • Xinhua Shen

  • Ruifang Cui

  • June 10, 2026

  • 0 min

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Clinical Report: A Transparent TimeMIL Approach for fNIRS in Psychiatry

Overview

This study introduces a time-aware multiple instance learning model (TimeMIL) applied to fNIRS data, achieving high accuracy in distinguishing schizophrenia from bipolar disorder. The model's interpretability framework enhances understanding of neurophysiological differences between these disorders.

Background

Differentiating schizophrenia (SCZ) from bipolar disorder (BD) is clinically significant due to overlapping symptoms that can lead to misdiagnosis and delayed treatment. Functional near-infrared spectroscopy (fNIRS) offers a promising method for capturing brain activity during cognitive tasks, potentially providing objective neurobiological markers for these conditions. The development of deep learning models like TimeMIL aims to improve diagnostic accuracy and support personalized care in psychiatric settings.

Data Highlights

GroupAccuracyAUC
TimeMIL0.928 ± 0.0160.984 ± 0.007

Key Findings

  • TimeMIL achieved an accuracy of 0.928 ± 0.016 in classifying SCZ, BD, and healthy controls.
  • The model demonstrated a macro-averaged AUC of 0.984 ± 0.007.
  • Attribution analyses revealed significant differences in the orbitofrontal cortex across groups.
  • SCZ-specific attribution patterns were noted in the frontal pole cortex and ventrolateral prefrontal cortex.
  • TimeMIL outperformed traditional models such as 1D-CNNs and Transformers.

Clinical Implications

The TimeMIL model provides a robust tool for enhancing the differential diagnosis of SCZ and BD, potentially reducing misdiagnosis rates. Its interpretability framework allows clinicians to understand the neurophysiological basis of predictions, fostering trust in the diagnostic process.

Conclusion

The application of TimeMIL to fNIRS data represents a significant advancement in psychiatric diagnostics, combining high accuracy with interpretability. Further validation in clinical settings is necessary to establish its utility in routine practice.

Related Resources & Content

  1. BMC Psychiatry (Springer), 2025 -- Neural association between mental symptoms and facial emotion recognition in deficit schizophrenia: an fNIRS study
  2. Frontiers in Neurology, 2026 -- Multimodal MRI reveals three-tiered pathological co-alterations in prolonged disorders of consciousness: structural disconnection, network disintegration, and regional hyperconnectivity
  3. Frontiers in Psychiatry, 2026 -- Abnormalcerebral-limbic functional connectivity between bipolar mania and bipolar depression under resting state
  4. BMC Psychiatry (Springer), 2025 -- Comparative Analysis of Biochemical Metabolism and Cognitive Abilities in Bipolar I versus Bipolar II Disorder
  5. NICE, 2025 -- Bipolar disorder: assessment and management
  6. Classification of functional near-infrared spectroscopy (fNIRS) signals in schizophrenia and bipolar disorder using deep learning methods - PubMed
  7. Molecular Psychiatry, 2025 -- The event-related potential components across psychiatric disorders: a systematic review and network meta-analysis
  8. Overview | Bipolar disorder: assessment and management | Guidance | NICE
  9. Classification of functional near-infrared spectroscopy (fNIRS) signals in schizophrenia and bipolar disorder using deep learning methods - PubMed
  10. The event-related potential components across psychiatric disorders: a systematic review and network meta-analysis | Molecular Psychiatry

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