Reduced microbiome alpha diversity in young patients with ADHD

Abstract

ADHD is a psychiatric disorder which is characterized by hyperactivity, impulsivity and attention problems. Due to recent findings of microbial involvement in other psychiatric disorders like autism and depression, a role of the gut microbiota in ADHD pathogenesis is assumed but has not yet been investigated. In this study, the gut microbiota of 14 male ADHD patients (mean age: 11.9 yrs.) and 17 male controls (mean age: 13.1 yrs.) was examined via next generation sequencing of 16S rDNA and analyzed for diversity and biomarkers. We found that the microbial diversity (alpha diversity) was significantly decreased in ADHD patients compared to controls (pShannon = 0.036) and that the composition (beta diversity) differed significantly between patients and controls (pANOSIM = 0.033, pADONIS = 0.006, pbetadisper = 0.002). In detail, the bacterial family Prevotellacae was associated with controls, while patients with ADHD showed elevated levels of Bacteroidaceae, and both Neisseriaceae and Neisseria spec. were found as possible biomarkers for juvenile ADHD. Our results point to a possible link of certain microbiota with ADHD, with Neisseria spec. being a very promising ADHD-associated candidate. This finding provides the basis for a systematic, longitudinal assessment of the role of the gut microbiome in ADHD, yielding promising potential for both prevention and therapeutic intervention.

Gut microbiota profiles of autism spectrum disorder and attention deficit/hyperactivity disorder: A systematic literature review.

“…No clear overall conclusion could be drawn from the studies. The two studies originating from Europe observed that the gut microbiota β-diversity of ADHD cases differed from controls, 65,66 whereas none of the two East-Asian studies observed any significant differences. , Furthermore, changes in individual bacteria were inconsistent between the four studies.…”

“…Only three studies used gender-matched cases and controls. 52,54,66 We also recorded information regarding the use of special diets or nutritional supplements, presence of GI symptoms as well as the use of medication. We found that for three studies investigating ASD 45,58,59 and one study investigating ADHD, the diet, or use of probiotics, of cases differed from that of controls.…”

“…Similarly, presence of GI symptoms (primarily constipation, but also diarrhea and abdominal pain) was common for ASD (reported in 31.5% of cases versus and 7.3% for controls), which was not seen for ADHD. All studies excluded participants who recently received antibiotics, while two studies investigating ADHD 65,66 included cases that received ADHD medication. No other medical treatments were observed to be prevalent in the studies (tables 3 and 4).…”

“…Following sample collection, the majority of studies stored the fecal samples at either −20°C or −80°C, while other studies used preserving buffers 47,50,57,59 or stored samples at 4°C. 54,65,66 Two studies did not provide information on storage of samples. 51,58 For DNA extraction, most studies used commercial spin column-based extraction kits, with approximately half of the studies implementing pretreatment steps to increase DNA extraction from gram-positive bacteria.…”

A Novel Index for Predicting Health Status Using Species-level Gut Microbiome Profiling

“…As researchers uncover more details regarding which gut commensals may play a significant role in host health, a promising application for this knowledge is towards developing a stool-based test to evaluate the health status tied to one's own gut microbiome. Among several measures of gut ecological properties, Shannon diversity in particular has frequently been applied for comparing gut microbiomes implicated in health and disease [16][17][18] . So far, however, there is no conclusive evidence that such gross characteristics are a reliable and accurate measure to explain variations in health traits 19,20 .…”