BBB	Blood–brain barrier
BD	Bipolar disorder
B-GOS	Galacto-oligosaccharide
CHR	Clinical high risk
CNS	Central nervous system
CRP	C-Reactive protein
CSF	Cerebrospinal fluid
DAT	Dopamine transporter
DISC	Disrupted-in-schizophrenia 1
DSM-5-TR	Diagnostic and Statistical Manual of Mental Disorders, 5th edition, Text Revision
FEP	First-episode psychosis
FES	First-episode schizophrenia
GAT	GABA transporter
GABA	γ-Aminobutyric acid
GBA	Gut–brain axis
GF	Germ-free
GI	Gastrointestinal
HPA Axis	Hypothalamic–pituitary–adrenal axis
5-HT	5-Hydroxytryptamine, Serotonin
INF	Interferon
IL	Interleukin
IP3	Inositol 1,4,5-triphosphate
LSD	Lysergic acid diethylamide
LPS	Lipopolysaccharide
MIA	Maternal immune activation
MK-801	Dizocilpine
α-MSH	α-Melanocyte-stimulating hormone
NAC	N-Acetylcysteine
NMDA	N-Methyl-D-aspartate
NMDAR	N-Methyl-D-aspartate glutamate receptor
PVIs	Parvalbumin interneurons
PCP	Phencyclidine
PET	Positron emission tomography
PFC	Prefrontal cortex
RNS	Reactive nitrogen species
ROS	Reactive oxygen species
SCFA	Short chain fatty acid
TGF-β1	Transforming growth factor-β1
TNF	Tumor necrosis factor
VTA	Ventral tegmental area