BAMBA – Treatment of ADHD with probiotics

The purpose of our research is to investigate the role of the intestinal microorganisms in attention-deficit hyperactivity disorder (ADHD) and to find out if treatment with supplements in the form of dietary fibers and lactic acid bacteria affect symptoms and daily function.

We have conducted a randomized placebo-controlled trial in Stockholm to get preliminary answers to these questions. For objective measures of possible effects, we determine the feces microorganisms with respect to both bacteria, fungi and viruses, and we measure immune activity and metabolites of the intestinal microorganisms in blood and urine samples. In support of our findings, similar trials are being carried out in the Eat2BeNice project, an EU-funded project with trials in three countries. The goal of our research is to contribute to evidence-based diet counseling for individuals with ADHD.

Description of the study that was conducted in Stockholm and the results we have found so far

The study, which was conducted in Stockholm, involved 99 children and 149 adults with an ADHD diagnosis through visits to PRIMA Child and Adult Psychiatry or Norra Stockholm's Psychiatry at St Eriksplan in Stockholm. Participants took a dietary supplement consisting of Synbiotic 2000 or placebo every day for 9 weeks. Which of the two treatments the participant received was randomized and was unknown to participants, nurses and researchers. The participants completed questionnaires about their symptoms and eating habits at the start of the study and after the 9 weeks. On these occasions, participants also provided blood samples, urine samples and stool samples.

Because the symptom picture may look different between children and adults, we analyzed the results for children and adults separately. The results showed that in both children and adults, ADHD symptoms decreased equally much for those who received placebo as for those who received Synbiotic 2000. In other words, Synbiotic 2000 had no effect on hyperactivity, impulsivity or inattention. However, Synbiotic 2000 reduced children's autistic traits more than placebo did, especially restrictive, repetitive, and stereotyped behaviors and interests. Synbiotic 2000 also reduced difficulties in managing emotions in adults more than placebo did. The degree of inflammation was measured in the blood. About half of the participants had slightly higher levels of a certain type of inflammation at the start. In children Synbiotic 2000 decreased the inflammation, and in adults the inflammation was decreased by oboth placebo and Synbiotic 2000. Preliminary results indicate that the decrease in inflammation was partly due to substances, so-called short-chain fatty acids, which bacteria produce in the colon and which pass easily into the blood. Previous international research has shown that the amount of these short-chain fatty acids is important for the intestines, blood vessels and brain.

That diet and the intestinal microorganisms can affect certain behaviors and certain types of inflammation has been shown previously by international research, especially in mice and rats. Similarly, several studies have shown that Synbiotic 2000 reduces the risk of infections and inflammation in difficult surgical procedures. However, this is the first study of the effect of a probiotic product for persons with ADHD. The analyses of the samples from this study are still ongoing to provide an understanding of why Synbiotic 2000 reduced autistic traits in children and improved emotion regulation in adults in this study. There is also a need for further studies with more participants that confirm our study results before we can concluded that what we have seen is true outside this study. A detailed study description and results can be found in the list of texts below. All results are always at group level. We never show any data from an individual study participant.

Links to the study description and results 

Inflammatory biotype of ADHD is linked to chronic stress: a data-driven analysis of the inflammatory proteome.
Schnorr I, Siegl A, Luckhardt S, Wenz S, Friedrichsen H, El Jomaa H, Steinmann A, Kilencz T, Arteaga-Henríquez G, Ramos-Sayalero C, Ibanez-Jimenez P, Rosales-Ortiz SK, Bitter I, Fadeuilhe C, Ferrer M, Lavebratt C, Réthelyi JM, Richarte V, Rommelse N, Ramos-Quiroga JA, Arias-Vasquez A, Resch E, Reif A, Matura S, Schiweck C
Transl Psychiatry 2024 Jan;14(1):37

Bacterial gut microbiome differences in adults with ADHD and in children with ADHD on psychostimulant medication.
Stiernborg M, Debelius JW, Yang LL, Skott E, Millischer V, Giacobini M, Melas PA, Boulund F, Lavebratt C
Brain Behav Immun 2023 May;110():310-321

Effects of a Synbiotic on Plasma Immune Activity Markers and Short-Chain Fatty Acids in Children and Adults with ADHD-A Randomized Controlled Trial.
Yang LL, Stiernborg M, Skott E, Xu J, Wu Y, Landberg R, Arefin S, Kublickiene K, Millischer V, Nilsson IAK, Schalling M, Giacobini M, Lavebratt C
Nutrients 2023 Mar;15(5):

Lower plasma concentrations of short-chain fatty acids (SCFAs) in patients with ADHD.

Yang LL, Stiernborg M, Skott E, Gillberg T, Landberg R, Giacobini M, Lavebratt C.J Psychiatr Res. 2022 Dec;156:36-43. doi: 10.1016/j.jpsychires.2022.09.042. Epub 2022 Sep 28.PMID: 36228390 

Effects of a synbiotic on symptoms, and daily functioning in attention deficit hyperactivity disorder - A double-blind randomized controlled trial.

Skott E, Yang LL, Stiernborg M, Söderström Å, Rȕegg J, Schalling M, Forsell Y, Giacobini M, Lavebratt C.Brain Behav Immun. 2020 Oct;89:9-19. doi: 10.1016/j.bbi.2020.05.056. Epub 2020 Jun 1.

Proinflammatory mediators and their associations with medication and comorbid traits in children and adults with ADHD.

Yang LL, Stiernborg M, Skott E, Söderström Å, Giacobini M, Lavebratt C.Eur Neuropsychopharmacol. 2020 Nov 4:S0924-977X(20)30914-7. doi: 10.1016/j.euroneuro.2020.10.005.

Early exposure to antibiotic drugs and risk for psychiatric disorders: a population-based study.

Lavebratt C, Yang LL, Giacobini M, Forsell Y, Schalling M, Partonen T, Gissler M.Transl Psychiatry. 2019 Nov 26;9(1):317. doi: 10.1038/s41398-019-0653-9.PMID: 31772217

Enteric short-chain fatty acids promote proliferation of human neural progenitor cells.

Yang LL, Millischer V, Rodin S, MacFabe DF, Villaescusa JC, Lavebratt C.J Neurochem. 2020 Sep;154(6):635-646. doi: 10.1111/jnc.14928. Epub 2019 Dec 18.PMID: 31784978

Exploring the gut-brain axis in Attention-Deficit Hyperactivity Disorder, Liu Yang

Tarmens och hjärnans kommunikation – Tarm-hjärna-axeln, gästkrönika av Catharina Lavebratt och Miranda Stiernborg, webbplats

Financial support

The study is financially supported by Vetenskapsrådet, Hjärnfonden, Bo and Ulla Lundevall, Ekhagastiftelsen, PRIMA Barn- och Vuxenpsykiatri AB and China Scholarship Council.

Team-leader: Catharina Lavebratt

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Catharina Lavebratt

Principal Researcher

Co-workers in the Translational Psychiatry Group:

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Elin Skott

Phd Student

Lilian Pagrot