Host-microbe interactions play a key role in brain development and function and in the etiology of neurodevelopmental disorders. Attention-deficit/hyperactivity disorder (ADHD) is a heterogeneous disorder that affects 1 in 20 children and results in poor life-time outcomes. However, the etiology of ADHD is unclear and its diagnosis and treatment are still challenging. Different factors reported to be associated with the risk of developing ADHD and/or linked to different ADHD manifestations have also been linked to shifts in gut microbiota composition, suggesting a link between the microbiota and the disorder. Here, we will perform a metagenome-wide association study and serum metabolomics profiling in a cohort of control and ADHD, 6-15 years, Chinese individuals. We aim to identify ADHD-associated gut microbial species linked to changes in circulating metabolites. We also aim to find the possible intervention strategy in ADHD by targeting the gut microbiota.

Inclusion Criteria:

Diagnoses of the children with ADHD were made in Xijing Hospital according to criteria described in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Children with ADHD had an IQ score above 70.

Exclusion Criteria:

Children who had a past history of or were currently affected by neurological diseases, including convulsive disorders or brain damage; or who had any evidence of comorbid psychiatric conditions, such as Tourette's syndrome, IQ below 70, pervasive developmental disorder (autism), bipolar disorder, psychosis, language difficulties or learning disorders (reading disorders, mathematics disorders and disorders of written expression).

All subjects were drug-naive at the time of recruitment, and the ADHD tests were administered before the subjects were given any medication. The subjects will be recruited from Xijing Hospital and elementary and secondary schools in China.