ReviewAnnals of general psychiatry2026
Pre-/pro and synbiotics on anxiety and depression symptoms: a GRADE assessed systematic review and meta-analysis of randomized controlled trials.
Review in Annals of general psychiatry, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundThe influence of pre-/pro-/synbiotics on depressive and anxiety symptoms remains ambiguous. This systematic review and meta-analysis aimed to clarify the impact of these interventions on mental health outcomes in adults.
methodsA systematic search was conducted across PubMed, Scopus, and Web of Science databases until May 10, 2025, to identify randomized controlled trials (RCTs) evaluating the effects of pre-/pro-/synbiotics on depressive and anxiety symptoms in adults. Random-effects models were used to compute pooled standardized mean differences (SMDs) and 95% confidence intervals (CIs). Heterogeneity was assessed using the I2 statistic. Publication bias was evaluated using funnel plots and Egger’s test.
resultsA total of 70 RCTs (65 for depression and 49 for anxiety) met the inclusion criteria and had intervention durations ranging from 2 to 24 weeks. Pre-/pro-/synbiotics supplementation significantly reduced depressive symptoms (SMD = −0.57; 95% CI: −0.71, −0.43, p < 0.001; I2 = 83.0%) and anxiety symptoms (SMD = −0.43; 95% CI: −0.59, −0.28, p < 0.001; I2 = 80.5%). Subgroup analyses for depression revealed larger effects in studies with sample size < 50, and in participants aged ≥ 50 years. Probiotics and synbiotics significantly reduced depression, while prebiotics did not. All three intervention types significantly reduced anxiety, with synbiotics showing the largest effect.
conclusionThis meta-analysis suggests that supplementation with pre-/pro-/synbiotics may have beneficial effects on depressive and anxiety symptoms in adults. However, due to substantial heterogeneity and the overall moderate methodological quality of included studies, these findings should be interpreted with caution. Importantly, these interventions should be considered as an adjunctive option to support mental health, not as a replacement for standard evidence-based treatments such as pharmacotherapy and psychotherapy. Further high-quality RCTs with standardized protocols are warranted to confirm these findings and establish definitive clinical recommendations.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.