Some mental disorders may have a more organic origin than previously thought. A recent study carried out in Slovakia reveals unexpected similarities in the intestinal ecosystem of children with autism, ADHD or anorexia. These similarities, observed even in the bacterial composition of their stools, raise questions among researchers. What if part of these disorders had their roots in the intestine?
Three troubles, the same invisible terrain
Autism, attention deficit disorder with or without hyperactivity (ADHD) and anorexia nervosa are three pathologies often considered separately, as their symptoms, mechanisms and target audiences differ. However, a study published in Neuroscience has highlighted an unexpected commonality. That of their link with marked intestinal dysbiosis. This exploratory research, led by Comenius University in Bratislava, was based on the analysis of the stools of 117 children, divided between patients suffering from one of these disorders and neurotypical controls.
Microbial diversity, generally synonymous with good intestinal health, appeared significantly reduced in autistic children and those with ADHD. As for the ratio between two large families of intestinal bacteria,
Bacteroidetes And Firmicutesthe researchers noted a significant change in all the children affected by a disorder. Several studies had already observed this same imbalance in various chronic inflammatory diseases.
The case of anorexia nervosa, often seen through an exclusively psychological prism, also reveals a specific intestinal signature. The young girls involved in this study had an unusual abundance of
Desulfovibriobacteria capable of reducing sulfate, often found in nutrient-poor environments. This finding is surprising and suggests that malnutrition is perhaps not the only thing that shapes this atypical flora.
What the imbalance of the intestinal microbiota reveals
Researchers have identified several bacteria involved, present in excess or on the contrary depleted, depending on the disorders. In the autistic and ADHD groups, levels ofEscherichia were abnormally high. Although these bacteria usually coexist safely with the body, they become problematic when they proliferate or migrate outside their area of origin. The teams also observed an over-representation of Desulfovibrio in the ADHD and anorexia groups, and found that anorexic children harbored more Cyanobacteria and of
Verrucomicrobiota.
Conversely, the Faecalibacteriumconsidered markers of good intestinal health, were less abundant in these children. These bacteria are known for their anti-inflammatory properties, and their absence is often reported in pathologies such as inflammatory bowel disease, depression and colorectal cancer.
The study also highlights the decline in certain beneficial species such as Bifidobacterium or the
Actinobacteriotaparticularly in autistic children. However, these microorganisms play an essential role in the fermentation of dietary fibers, immune regulation and the production of vitamins.
These alterations, which can result from specific eating behaviors (restrictions, selectivity, rituals) as suggested in a review published by the National Autistic Society, are not always the direct consequence of the disorder. On the contrary, they could contribute to its maintenance, or even its appearance.
The trail of a shared biological base between disorders
The links between brain and intestine, now well documented, offer a new framework for understanding certain neurodevelopmental or psychiatric disorders. The Slovak study, relayed by ScienceAlert, suggests that these similar microbial profiles could act as behavior modulators, via the production of satiety hormones or neurotransmitters, or even by the induction of micro-inflammations affecting the nervous system.
Some biomarkers, such as peptide YY (PYY) or leptin (key hormones in appetite regulation) showed reduced levels in children with anorexia or ADHD. Their alteration could reflect a disrupted dialogue between intestine and brain, amplified by an unbalanced microbiota. This type of imbalance could maintain a vicious cycle between eating disorders, inflammation and mental disorders.
This common biological ground does not mean that the disorders share the same cause, but it could contribute to their vulnerability or influence their expression. The idea of a shared microbial factor opens the way to a more comprehensive approach to diagnosis and treatment. Personalized diets, targeted probiotics or interventions on the gut-brain axis could in the future complement traditional therapeutic approaches.
With an unwavering passion for local news, Christopher leads our editorial team with integrity and dedication. With over 20 years’ experience, he is the backbone of Wouldsayso, ensuring that we stay true to our mission to inform.
