Probiotics for Autism Spectrum Disorders: a Randomized Controlled Trial (The PASD Study)

NCT07345585 | Recruiting

• 1 other identifier: 38/2023
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 1

Brief Summary

Autism spectrum disorders (ASD) are a group of severe neurodevelopmental conditions characterized by impaired communication and social interaction, as well as repetitive/stereotyped behaviors deriving from a combination of genetic and environmental factors. The ASD diagnosis rates increased dramatically over the past number of decades. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) describes a worldwide prevalence of approximately 1%. The prevalence of ASD is 1 in 59 individuals in the US reported by the Centers for Disease Control and Prevention. According to the latest data from the Italian National Observatory for ASD, the actual prevalence in Italy is about 1/77 for children aged between 7 and 9 years, with a 4.4 times higher prevalence in male. The origin of ASD is still largely undefined. It has been hypothesized a possible role for the influence of early life alteration of gut microbiome (GM). We demonstrated an imbalance in Bacteroidetes and Firmicutes phyla with a decrease in Bacteroidetes/Firmicutes ratio in the GM of pediatric patients affected by ASD. Similar data have been observed by others. Data from ASD animal model confirm the presence of GM dysbiosis with significant correlation with behavioral, gastrointestinal and immunologic alterations. Altogether these data support the hypothesis that GM dysbiosis could be involved in the ASD pathogenesis. The ASD children present an increased prevalence of functional gastrointestinal disorders (FGIDs), mainly chronic constipation, functional diarrhea, and irritable bowel syndrome (IBS). A role for GM has been suggested also for these conditions. The presence of these disorders negatively influence the disease severity and the parental quality of life of ASD children. Starting from all these considerations GM is becoming a possible target of intervention for pediatric ASD. Probiotics are one of the most investigated strategy for a beneficial modulation of GM. Probiotics are commonly defined as live microorganisms which when ingested in adequate amounts confer a beneficial effect on the host. The most used probiotics in the pediatric age are Saccharomyces and Lactobacillus strains including Lactobacillus rhamnosus GG (LGG). Data report a beneficial influence elicited by LGG on GM structure and function. This probiotic resulted also effective in treating FGIDs patients. Preliminary evidence suggest the potential efficacy of probiotics for FGIDs treatment in ASD children. Altogether these evidence strongly support the hypothesis that LGG could exert a beneficial action in ASD children. The purpose of this study is to evaluate the therapeutic efficacy of LGG on FGIDs in ASD children.

Conditions

Autism Spectrum Disorder

Outcome Measures

Primary Outcomes (1)

• Functional gastrointestinal disorders (FGIDs) severity

  Severity index of gastrointestinal symptoms (GI Severity Index, GSI) - Minimum Score: 0 (Indicates absence of gastrointestinal symptoms or optimal bowel regularity) Maximum Score: 17 (Represents the highest severity of symptoms reported in the questionnaire)

  At 16 weeks of treatment

Secondary Outcomes (9)

• Kinetics of Lactobacillus rhamnosus GG (LGG)

  At baseline and at 4 weeks, 8 weeks and 12 weeks of treatment

• Duration of the LGG impact on FGIDs

  At baseline and at 4 weeks and 12 weeks from the end of treatment

• Gut Microbiome (GM) composition

  At baseline and at 16 weeks of treatment

• GM function: fecal short chain fatty acids (SCFAs) levels

  At baseline and at 16 weeks of treatment

• ASD children behavior

  At baseline, at 4 weeks, at 8 weeks, at 12 weeks and at 16 weeks of treatment, and at 4 weeks and 12 weeks from the end of treatment

Study Arms (2)

Probiotic

EXPERIMENTAL

Lactobacillus rhamnosus GG

Other: Lactobacillus rhamnosus GG

Placebo

PLACEBO COMPARATOR

Placebo

Other: Placebo

Interventions

Lactobacillus rhamnosus GG OTHER

Lactobacillus rhamnosus GG

Probiotic

Placebo OTHER

Placebo

Placebo

Eligibility Criteria

• Age: 4 Years - 12 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17)

You may qualify if:

• children aged 4-12 years
• children of both sex
• children with a sure diagnosis of ASD and presence of FGIDs with a GSI ≥7 from at least 3 months.

You may not qualify if:

• children aged \<4 or \>12 years
• uncertain ASD and/or FGIDs diagnosis
• FGIDs duration lasting \<3 months
• concomitant presence of other chronic conditions (adverse food reactions; genetic and metabolic disorders; malformations of GI, respiratory or urinary tract; neurologic diseases; immunodeficiencies; diabetes; cardiovascular diseases; autoimmune diseases; chronic infections; chronic respiratory, GI or urinary tract diseases; obesity; tumors; malnutrition).
• use of antibiotics and/or pre-/pro-/ synbiotics during the 6 months prior to enrolment
• participation into other clinical trials during the last 12 months.

Sponsors & Collaborators

• Federico II University: lead

Study Sites (1)

Department of Traslational Medical Science - University of Naples Federico II

Naples, 80131, Italy

RECRUITING

MeSH Terms

Conditions

Autism Spectrum Disorder

Condition Hierarchy (Ancestors)

Child Development Disorders, Pervasive; Neurodevelopmental Disorders; Mental Disorders

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, CARE PROVIDER
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: MD,PhD,Prof

Study Record Dates

• First Submitted: December 9, 2025
• First Posted: January 15, 2026
• Study Start: January 1, 2023
• Primary Completion: March 1, 2026
• Study Completion: March 1, 2026
• Last Updated: January 15, 2026

Record last verified: 2025-10

Data Sharing

• IPD Sharing: Will not share

Locations

IT (1)