The gut microbiome in children with mood, anxiety, and neurodevelopmental disorders: An umbrella review

Abstract

Research on the gut microbiome and mental health among children and adolescents is growing. This umbrella review provides a high-level overview of current evidence syntheses to amalgamate current research and inform future directions. Searches were conducted across seven databases for peer-reviewed pediatric (<18 years) review literature. Studies reporting gut microbiome composition and/or biotic supplementation on depression, bipolar disorder, anxiety, attention deficit hyperactivity disorder, autism spectrum disorder (ASD), or obsessive-compulsive disorder (OCD) were included. Deduplication and screening took place in Covidence. A sensitivity analysis was conducted to assess the degree of primary study overlap. Among the 39 included review studies, 23 (59%) were observational and 16 (41%) were interventional. Most reviews (92%) focused on ASD. Over half (56%) of the observational and interventional reviews scored low or critically low for methodological quality. A higher abundance of Clostridium clusters and a lower abundance of Bifidobacterium were consistently observed in ASD studies. Biotic supplementation was associated with ASD symptom improvement. Gut microbiome-mental health evidence syntheses in child and youth depression, anxiety, bipolar disorder, and OCD are lacking. Preliminary evidence suggests an association between specific microbiota and ASD symptoms, with some evidence supporting a role for probiotic supplementation ASD therapy.

Keywords: autism; children and adolescents; mental health; microbiome; umbrella review.

Figure 1.

PRISMA flowchart.

Figure 2.

Reported abundance of gut operational taxonomic units in youth with ASD and ADHD (n = 23). The outer circle represents the genus level, with outer colours distinguishing the phylum. Dark blue arrows indicate reviews of ASD, and light blue arrows indicate reviews of ADHD. ↑ indicates higher abundance in youth with the disorder, while ↓ indicates lower abundance in the disorder.

Figure 3.

Reported changes in gut microbiota operational taxonomic units following prebiotic, probiotic, and synbiotic supplementation among youth with ASD (n = 16). The outer circle represents the genus level, with outer colours distinguishing phylum. Dark blue arrows indicate reviews of ASD. ↑ indicates higher abundance in youth with the disorder compared to baseline, while ↓ indicates lower abundance in the disorder compared to baseline.

Figure 4.

Reported increase/decrease in abundance of gut operational taxonomic units in youth with autism spectrum disorder (ASD) (dark blue) and ADHD (light blue) across (A) included systematic reviews (n = 23) and (B) after overlap bias was minimised (n = 10).

Figure 5.

Reported increase/decrease in abundance of gut operational taxonomic units in youth with ASD following prebiotic (black), probiotic (red), or synbiotic (green) supplementation (A) across included interventional systematic reviews (n = 16) and (B) after overlap bias was minimized (n = 6).