Psychobiotics in pediatric autism spectrum disorder: A systematic review of efficacy, mechanisms, and clinical translation

Table 3 Effects of probiotic supplementation on gastrointestinal symptoms in children with autism spectrum disorder

Ref.	Country	Study design	Participants (n)	Probiotic intervention	Duration	Gastrointestinal outcome measures	Main gastrointestinal findings
Santocchi et al[30]	Italy	Randomized controlled trial	100	Multi-strain probiotic	6 months	GSI	Significant improvements in GI symptoms, particularly in children with baseline gastrointestinal disturbances
Shaaban et al[28]	Egypt	Randomized placebo-controlled trial	30	Multi-strain probiotic	3 months	GI symptom questionnaire	Significant reductions in constipation, abdominal pain, and diarrhea compared with placebo
Narula Khanna et al[25]	India	Randomized placebo-controlled trial	180	Multi-strain probiotic	3 months	GSI	Probiotic supplementation significantly improved constipation and diarrhea scores, with concurrent behavioral improvement
Liu et al[24] (PS128 trial)	Taiwan	Randomized double-blind trial	71	Lactobacillus plantarum PS128	4 weeks	GI symptoms (secondary outcomes)	No major GI changes reported; probiotic effects were primarily observed in behavioral domains

GI: Gastrointestinal; GSI: Gastrointestinal severity index.