Attention-Deficit/Hyperactivity Disorder Etiology and Symptomatology: The Potential Role of the Gut Microbiota-Gut-Brain Axis

A healthy human microbiome is crucial for normal physiological functioning of the human host. The gastrointestinal tract harbors a densely populated community of microbes that exhibits sexual dimorphism, and dysbiosis of this community has been associated with chronic human disease states ranging from metabolic diseases to neuropsychiatric disorders (NPDs). The gut microbiota-gut-brain axis (GMGBA) is a bi-directional pathway that facilitates the interaction of the gut microflora with human host physiological functions. Recently, research surrounding the potential roles of the GMGBA in the development of NPDs (e.g., depression, anxiety, and autism spectrum disorders) has increased; however, attention-deficit/hyperactivity disorder (ADHD), a NPD that affects an estimated 8.4% of children and 4% of adults in the United States, remains under-studied. Over the 2020-21 academic year, a proposal was developed for a project aimed at preliminarily characterizing gut microbial composition in adult human subjects based on host sex and ADHD diagnosis using high-throughput 16S rRNA sequencing. Additionally, prediction of the functional capacity of the subjects’ gut microbiomes based on presence or absence of ADHD diagnosis and host sex will be carried out using the PICRUSt2 and HUMAnN3 pipelines. The proposed project seeks to contribute preliminary data to the overall understanding of the physiological underpinnings of ADHD in the human supraorganism. Ultimately, the hope is that this research will provide a springboard for future studies that facilitate the translation of experimental knowledge into increasingly efficacious clinical practices for the treatment of ADHD