Introduction
Methods
Literature search for gut microbiota studies in ADHD
Results
Literature search
Characteristics of studies (see Table 2 )
Samples in studies
Dietary pattern
ADHD medication and consumption of probiotic/prebiotic/antibiotic
Psychiatric condition, allergic history, and other medical conditions
Methodology
Clinical assessments
No. | Study | Country | Total of samples | Agec | Diagnostic tool | |
---|---|---|---|---|---|---|
ADHD | Control | |||||
1 | Aarts et al. [12] | Netherlands | 19 ADHD, 77 controlsa | 19.5 | 27.1 | K-SADS based on DSM-IV |
2 | Jiang et al. [9] | China (Zhejiang) | 51 ADHD, 32 controls | 8.47 | 8.5 | K-SADS-PL based on DSM-IV |
3 | Prehn-Kristensen et al. [14] | Germany | 14 ADHDb, 17 controlsb | 11.9 | 13.1 | K-SADS-PL (Germany translation) based on DSM-IV |
4 | Wang et al. [10] | China (Taiwan) | 30 ADHD, 30 controls | 8.4 | 9.3 | K-SADS-E (China version) based on DSM-IV-TR |
5 | Wan et al. [11] | China (Beijing) | 17 ADHD, 17 controls | 8 (median) | 8 (median) | K-SADS based on DSM-5 |
6 | Szopinska-Tokov et al. [13] | Netherlands | 41 ADHD, 15 subthreshold ADHD, 47 controls | ADHD = 20,2; subthreshold ADHD = 20,2 | 20.5 | K-SADS based on DSM-IV |
Microbiota analysis
No. | Study | Genetic analysis | Characteristic of population | ||||
---|---|---|---|---|---|---|---|
Medical history | Antibiotic usage | Probiotic/prebiotic usage | ADHD medication | Dietary patterns | |||
1. | Aarts et al. [12] | 16S rRNA gene sequencing using Titanium sequencing chemistry | No information | No information | No information | No information | No information |
Region: V3–V4 | |||||||
Pipeline analysis: QIIME ver 1.2 | |||||||
Database: ENA | |||||||
2. | Jiang et al. [9] | 16s rRNA gene pyrosequencing using Illumina MiSeq platform with TruSeqTM DNA Sample Prep Kit | Excluded sample with digestive symptoms, depressive and anxiety symptoms, obesity, atopic diseases (allergic rhinitis, asthma, eczema), and other severe diseases 2 months prior to samples collection | No use of antibiotics 2 months prior to samples collection | No use of probiotic/prebiotic 2 months prior to samples collection | No history of ADHD medication | Excluded vegetarian and non-vegetarian diet (using questionnaire filled by parents) |
Region: V3–V4 | |||||||
Pipeline analysis: QIIME | |||||||
3. | Prehn-Kristensen et al. [14] | DNA amplification on primer 27F-338R using Illumina Miseq | No information | No information | No information | 10 samples of ADHD had been taking ADHD medication for more than a year | The participants took notes on their food intake for fast food, meat/sausage/cold cuts, fruits/vegetables, and yoghurt/dairy products (using 4-point scales) |
Region: V1–V2 | |||||||
Pipeline analysis: Mothur | |||||||
4. | Wang et al. [10] | 16S rRNA gene sequencing | Excluded samples with history of neuropsychiatry disorder or any major diseases | No recent use of antibiotic | No recent use of antibiotic | No history of ADHD medication | Excluded vegetarian diet (using FFQ) |
Region: V3–V4 | |||||||
5. | Wan. et al. [11] | Shotgun metagenomic sequencing using Illumina Novaseq platform | Excluded samples with history of respiratory/digestive infection in a month prior to samples | No information | No use of probiotic 1 month prior to samples collection | No information | Excluded vegetarian diet. The participants were asked to maintain their regular dietary patterns for 1 |
Pipeline analysis: HUMAnN2 ver 0.11.2 | |||||||
Database: Integrated Gene Catalog and KEGG | Collection, history of digestive/chronic diseases, BMI < 20 kg/m2, and allergic rhinitis/asthma | Week prior to samples collection (using food diary) | |||||
6. | Szopinska-Tokov. et al. [13] | 16s rRNA gene sequencing | No information | No recent use of antibiotic | No recent use of probiotic | There were history of ADHD medication | No information |
Region: 27F-DegS-338RI-II | |||||||
Pipeline analysis: NG-Tax 16s rRNA | |||||||
Database: SILVA |
Diversity analysis (see Table 3)
No. | Study | Alpha diversity index | Alpha diversity | Beta diversity index | Beta diversity |
---|---|---|---|---|---|
1 | Aarts et al. [12] | Shannon, Chao1 | No significant differences | – | – |
2 | Jiang et al. [9] | ACE, Chao1, Shannon, Simpson | No significant differences | Unweighted and weighted UniFrac, Bray–Curtis PCoA | Could not be differentiated |
3 | Prehn-Kristensen et al. [14] | Shannon, Chao1 | Decreased (pShannon = 0.036) | ANOSIM, ADONIS, Betadisper from the R package vegan v2.4–1 | Differed significantly (pANOSIM = 0.033; pADONIS = 0.006; pbetadisper = 0.002) |
4 | Wang et al. [10] | Shannon, Chao1 | Shannon index (p = 0.0378) and Chao index (p = 0.0351) were increased significantly in ADHD Simpson index (p = 0.0339) was decreased significantly in ADHD | Unweighted & weighted UniFrac, PCoA | No significant differences |
5 | Wan et al. [11] | Shannon, Chao1, Simpson | No significant differences | – | – |
6 | Szopinska-Tokov et al. [13] | Shannon–Wiener, Faith’s phylogenetic diversity | No significant differences | UniFrac distance metric, ADONIS, Betadisper ver 2.5–2, PCoA | Differed significantly (10 genera showed nominal difference) |
Findings (see Table 4 )
No. | Study | Gut microbiota profiles |
---|---|---|
1 | Aarts et al. [12] | Phylum: ↑: Actinobacteria Order: ↓: Clostridiales Family: ↑: Rikenellaceae, Porphyromonadaceae Genus: ↑: Bifidobacterium, Eggerthella |
2 | Jiang et al. [9] | Family: ↑: Peptostreptococcaceaea, Moraxellaceaeb, Xanthomonadaceaeb, Peptococcaceaeb ↓: Alcaligenaceaea Genus: ↓: Faecalibacteriuma, Dialistera, Lachnoclostridiumc, Sutterellab |
3 | Prehn-Kristensen et al. [14] | Family: ↑: Neisseria, Bacteroidaceae Genus: ↑: Neisseria ↓: Prevotella OTU level: ↑: Bacteroides OTU_7, Bacteroides OTU_577 |
4 | Wang et al. [10] | Phylum: ↑: Fusobacteria Genus: ↑: Fusobacterium Species: ↑: Bacteroides uniformis, Bacteroides ovatus, Sutterella stercoricanis ↓: Bacteroides coprocola |
5 | Wan et al. [11] | Genus: ↑: Odoribacterd, Enterococcusb ↓: Faecalibacteriumd, Veillonellaceaed |
Species: ↑: Bacteroides caccaed, Odoribacter splanchnicusd, Paraprevotella xylaniphilad, Veillonella parvulad, Roseburia intestinalisd, Odoribacteraceaeb, Enterococcaceaeb ↓: Faecalibacterium prausnitziid, Lachnospiraceae bacteriumd, Ruminococcus gnavusd, Ruminococcaceaeb | ||
6 | Szopinska-Tokov et al. [13] | Genus: ↑: Clostridiales_g__, Family_XII_AD3011_group, Ruminiclostridium_9, Ruminococcaceae_NK4A214_group, Ruminococcaceae_UCG_003, Ruminococcaceae_UCG_004, Ruminococcaceae_UCG_005, Ruminococcaceae_g_uncultured, Ruminococcus_2, Dialistere ↓: Haemophilus, Phascolarctobacteriume |