Exploration of Immunology

Table 1. Stress and inflammation in depressive episode subtypes and pain

Features	Melancholic episode	Atypical episode	Pain
Mood	Flat, anhedonia	Reactive	-
Worsening of mood	Morning	Evening	-
Insomnia	Early awakening	Hypersomnia	Insomnia
Eating behavior	Hyporexia	Craving for carbohydrates	-
Activity	Slowdown	Leaden paralysis	Fatigue
Innate immunity	↑	↑	↑
Adaptive immunity	↑	↑	↑
TNF-α	↑	↑	↑
IL-1	↑	↑	↑
IL-6	↑	-	↑
CRP	↑	-	↑
BBB	Decreased	-	-
DexST	Suppressed	Normal	Normal
SNS	↑	-	↑
CRF	↑	↓	-
ACTH	↑	↓	Normal stress stimulus response
Cortisol	↑ at basal level	Reduced production	Blunted stress stimulus response
KYN	↑	-	↑
5HT	↓	↓	↓
GABA	↓	-	↓
BDNF	↓	↓	↓

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↑: hyperactivity or increased level; ↓: hypoactivity or decreased level; -: no date. TNF-α: tumor necrosis factor-α; IL-1: interleukin-1; CRP: C-reactive protein; BBB: blood-brain barrier; DexST: dexamethasone suppression test; SNS: sympathetic nervous system; CRF: corticotropin-releasing factor; ACTH: adrenocorticotropic hormone; KYN: kynurenine; 5HT: serotonin; GABA: gamma-aminobutyric acid; BDNF: brain-derived neurotrophic factor

Declarations

Author contributions

AC: Conceptualization, Investigation, Writing—original draft, Writing—review & editing. GC: Writing—original draft, Validation, Writing—review & editing, Supervision. All authors read and approved the submitted version.

Conflicts of interest

The authors declare that they have no conflicts of interest.

Ethical approval

Not applicable.

Consent to participate

Not applicable.

Consent to publication

Not applicable.

Availability of data and materials

Not applicable.

Funding

Not applicable.

Copyright

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