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Therapeutic efficacy of probiotics for symptoms of attention-deficit hyperactivity disorder in children and adolescents: meta-analysis.

  • 2024-01
  • BJPsych open 10(1)
    • Shun-Chin Liang
    • Cheuk-Kwan Sun
    • Chih-Hua Chang
    • Yu-Shian Cheng
    • Ruu-Fen Tzang
    • Hsien-Jane Chiu
    • Ming Yu Wang
    • Ying-Chih Cheng
    • Kuo-Chuan Hung

Study Design

Type
Review
Sample size
n = 379
Population
seven trials involving 379 participants (mean age 10.37 years, range 4-18 years)
Methods
Meta-analysis of seven randomized placebo-controlled trials identified through searching major databases from inception to April 2023

Background

The efficacy of probiotics as a therapeutic alternative for attention-deficit hyperactivity disorder (ADHD) remain unclear.

Aims

To investigate the effectiveness of probiotics for symptoms of ADHD and identify possible factors affecting their efficacy.

Method

Randomised placebo-controlled trials were identified through searching major databases from inception to April 2023, using the main keywords 'probiotics' and 'ADHD' without limitation on languages or geographic locations. The outcome of interest included improvement in total symptoms of ADHD, symptoms of inattention and hyperactivity/impulsivity, and drop-out rate. Continuous and categorical data were expressed as effect sizes based on standardised mean differences (SMDs) and odds ratios, respectively, with 95% confidence intervals.

Results

Meta-analysis of seven trials involving 379 participants (mean age 10.37 years, range 4-18 years) showed no significant improvement in total symptoms of ADHD (SMD = 0.25; P = 0.12), symptoms of inattention (SMD = 0.14; P = 0.3) or hyperactivity/impulsivity (SMD = 0.08; P = 0.54) between the probiotic and placebo groups. Despite non-significance on subgroup analyses, there was a large difference in effect size between studies using probiotics as an adjunct to methylphenidate and those using probiotics as supplementation (SMD = 0.84 v. 0.07; P = 0.16), and a moderate difference in effect size between studies using multiple strains of probiotics and those using single-strain regimens (SMD = 0.45 v. 0.03; P = 0.19).

Conclusions

Current evidence shows no significant difference in therapeutic efficacy between probiotics and placebos for treatment of ADHD symptoms. However, albeit statistically non-significant, higher therapeutic efficacies associated with multiple-strain probiotics or combining probiotics with methylphenidate may provide direction for further research.

Research Insights

  • Lactobacillus casei PXN 37→Improved ADHD-Related Symptoms

    Meta-analysis of seven trials involving 379 participants ... showed no significant improvement in total symptoms of ADHD (SMD = 0.25; P = 0.12), symptoms of inattention (SMD = 0.14; P = 0.3) or hyperactivity/impulsivity (SMD = 0.08; P = 0.54) between the probiotic and placebo groups.

    Effect
    Neutral
    Effect size
    Small
  • Lactobacillus rhamnosus PXN 54→No Significant Improvement in ADHD Symptoms

    Meta-analysis of seven trials involving 379 participants ... showed no significant improvement in total symptoms of ADHD ... symptoms of inattention ... or hyperactivity/impulsivity ... between the probiotic and placebo groups.

    Effect
    Neutral
    Effect size
    Small
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