Table 1.
Characteristics of participants.
Fig 1.
Alpha diversity of stool samples.
Alpha-diversity, measured by observed species and Shannon diversity Index is plotted for patients with ADHD (red) and controls (green). The line inside the box represents the median, while the whiskers represent the lowest and highest values within the 1.5 interquartile range (IQR). Outliers as well as individual sample values are shown as dots. Statistical testing showed no difference for observed species (pObserved = 0.25), while Shannon diversity was significantly decreased in ADHD compared to controls (pShannon = 0.036).
Fig 2.
Non-metric multidimensional scaling (NMDS) of ADHD samples and healthy controls.
NMDS is an unconstrained, distance-based ordination method which was performed with Bray-Curtis dissimilarity. Points represent samples. Samples that are more similar to one another are ordinated closer together. ADHD patients are plotted as red triangles, and controls are represented as green dots. The groups show significant differences in similarity tested by ANOSIM (pANOSIM = 0.033).
Fig 3.
Results of LDA effect size (LefSe) analysis of male ADHD patients compared to healthy controls.
The LEfSe analysis finds taxa which are significantly more abundant in one group, while the bar size represents the effect size of the taxa in the particular group. (A) family level, (B) genus level, (C) OTU level (97% similarity). There were no taxa differences at the order and phylum level. The threshold p-value was 0.05.
Fig 4.
Differentiation of participants´ microbiomes.
RDA biplot at OTU level with Hellinger-transformed data. Redundancy analysis is a constrained method based on multiple linear regression which enables correlation of explanatory variables with the RDA axes. The black dots represent individuals without ADHD; the green dots, individuals with ADHD diagnosis. Species and factors correlated with the RDA axes were determined by the envfit function of the R package vegan, the cut-off for plotted results was p = 0.01.