Attention deficit disorder associated with impairment of the intestinal microbiota
Impairment of the intestinal microbiota could be involved in the development of attention deficit disorder with or without hyperactivity (ADHD), according to a Chinese study which supports the hypothesis of a role played by intestinal microorganisms in psychiatric diseases.
Attention deficit disorder with or without hyperactivity (ADHD) is a neurodevelopmental disorder which appears in childhood. Its causes are still poorly understood, but the involvement of environmental risk factors such as exposure in utero to antibiotics or delivery by cesarean section are suspected: two events which both impair the early establishment of the intestinal microbiota in children. At this time however, no study has dealt with the possible link between ADHD and the composition of the intestinal microbiota, whose role in some psychiatric diseases (schizophrenia, bipolar disorder, depression) has been demonstrated.
A different intestinal microbiota
Chinese researchers therefore tried to determine whether the intestinal microbiota of patients suffering from ADHD was different from that of individuals who did not suffer from this disorder, and whether the differences were associated with symptoms of the disease. The stools of 83 children (51 with ADHD and 32 control subjects) were collected for comparison of the intestinal microbiotas. Although no differences were observed in terms of microbial diversity, the researchers noted that three bacterial genera–including Faecalibacterium–were markedly more abundant in the children diagnosed with ADHD than in the control children. Taking their investigations forward and on the basis of information reported by the parents, they concluded that the lower the level of Faecalibacterium in the intestinal microbiota, the more pronounced the disease symptoms were.
Faecalibacterium, a new marker for ADHD?
These results add to those of other studies establishing a link between a low level of Faecalibacterium and different psychiatric disorders (depression, bipolar disorder) as well as some other studies focusing on the adult population with ADHD, which is thought to display increased levels of certain bacteria. The authors consider that this new study confirms the role of the intestinal microbiota in the development of psychiatric disorders. Faecalibacterium, in particular, could represent a new marker for ADHD if its role in the disease were to be confirmed in the future.
Jiang et al. Gut microbiota profiles in treatment-naïve children with attention deficit hyperactivity disorder. Behavioural Brain Research 347 (2018) 408–413