TABLE 1.

Changes in gut microbiota in various neuropsychiatric and neurodegenerative diseases.

Disorder	Symptoms	Changes in gut microbiota	References
Depression and anxiety	Persistent and significant tension and restlessness	↓ Bifidobacterium and lactobacillus ↑ Bacteroidetes, Proteobacteria, and Actinobacteria ↓ Firmicutes ↓ Coprococcus and Dialister	Jiang et al., 2015; Aizawa et al., 2016; Valles-Colomer et al., 2019
Schizophrenia	Psychosis, delusion, cognitive dysfunction, Apathy, social withdrawal	↑ Bacteroidetes and Actinobacteria ↑ Streptococcus gordonii, S. thermophilus, and Streptococcus sp. (oral taxon 071) ↑ Candida ↑ Eubacterium ↓ Neisseria, Haemophilus, and Capnocytophaga	Castro-Nallar et al., 2015
Autism spectrum disorder	Impaired social communications and interactions, stereotyped behaviors, and cognitive inabilities	↑ Clostridia and Desulfovibrio ↓ Bifidobacterium ↑ Bifidobacterium longum	Grimaldi et al., 2018; Cryan et al., 2019
Bipolar disorder	Emotional highs (mania or hypomania) and lows (depression).	↓ Faecalibacterium	Evans et al., 2017
Attention deficit/hyperactivity disorder	Inattention, impulsivity, hyperactivity, and cognitive impairment	↑ Blautia ↑ Bifidobacterium	Aarts et al., 2017; Wang et al., 2022
Alzheimer’s disease	Cognitive decline, impairments in the memory, behavior and learning	↑ Firmicutes and Proteobacteria ↓ Bacteroidetes ↓ Firmicutes ↑ Bacteroidetes ↓ Bifidobacterium	Vogt et al., 2017; Nagpal et al., 2019
Parkinson’s disease	Rigid movements, tremor, and abnormal gait	↓ Prevotellaceae ↑ Enterobacteriaceae ↑ Lactobacillus ↓ Clostridium coccoides ↓ Bacteroides fragilis	Hasegawa et al., 2015; Scheperjans et al., 2015
Multiple sclerosis	Motor deficits, blurry vision, and sensibility modulations	↓ Butyricimonas ↑ Methanobrevibacter and Akkermansia ↑ Akkermansia muciniphila and Acinetobacter calcoaceticus ↓ Parabacteroides distasonis	Jangi et al., 2016; Cekanaviciute et al., 2017