Role of inflammation in depression relapse

Table 1 Summary of the eight main abnormalities related to inflammation and associated consequences in patients with MDD

Main abnormalities	Consequence
Increased levels of TNF-α, IL-6, and CRP and decreased levels of IL-1β and IL-8 [22]	rMDD
Increased activity of corticotropin-releasing hormone and hyperactivity of the HPA axis [15]	MDD progression and predicted recurrence
Higher levels of IL-6 or CRP [23, 24]	Subsequent development of depressive symptoms (e.g., tiredness, lack of energy, sleep problems, and changes in appetite)
Increased inflammatory activity [25]	TRD
Intestinal microbes [26, 27]	Tryptophan metabolism and the levels of gamma-aminobutyric acid, dopamine, and serotonin
Cognitive behavior therapy [28] Vagus nerve stimulation [29, 30] Inflammation [31, 32]	Inflammatory processes Relief of MDD symptoms Anhedonia and motor retardation

Abbreviations: CRP C-reactive protein, HPA hypothalamic−pituitary−adrenal, IL-6 interleukin-6, rMDD recurrent major depressive disorder, TNF-α tumor necrosis factor-α, TRD treatment-resistant depression

ISSN: 1742-2094