Experimental studies showing depression and anxiety symptoms improvement induced by probiotic interventions in PD.
| Study (year) | Probiotic(s) | Duration | Dose/Presentation | Outcome |
|---|---|---|---|---|
| Human studies | ||||
| Sun et al. (2022) [82] | Probio-M8 (Bifidobacterium animalis subsp. lactis) | 3 months | 2 g of Probio-M8 powder (3 × 1010 CFU/day; maltodextrin as excipient) daily | Depression (HAMD-17): significant improvement vs. control (p < 0.001). Anxiety (HAMA): significant improvement vs. control (p < 0.001). |
| Yang et al. (2023) [92] | Lacticaseibacillus paracasei strain Shirota (LcS) | 12 weeks | Fermented milk drink containing 1 × 1011 CFU of LcS, once daily | Depression (HAMD-17): significant improvement vs. control (p = 0.010). Anxiety (HAMA): significant improvement vs. control (p = 0.005). |
| Zeng et al. (2024) [93] | Bacteroides fragilis BF839 + earthworm protein | 12 weeks | 10 g supplement dissolved in 200 mL water, twice daily (each 10 g containing 106 BF839 and 0.3 g earthworm protein) | Depression: significant reduction in HAMD-24 score (−3.91 ± 3.99 vs. +1.15 ± 3.42, p < 0.001). Anxiety: significant reduction in SAS score (−7.04 ± 5.71 vs. −1.23 ± 2.34, p < 0.001). Both improvements sustained through 12 weeks compared to placebo. |
PD: Parkinson’s disease; HAMD-17: Hamilton Depression Rating Scale 17; HAMA: Hamilton Anxiety Rating Scale; SAS: Self-Rating Anxiety Scale.
SPG: Conceptualization, Formal analysis, Investigation, Methodology, Project administration, Resources, Supervision, Visualization, Writing—original draft, Writing—review & editing. DHT: Conceptualization, Formal analysis, Investigation, Resources, Writing—original draft. FES: Conceptualization, Formal analysis, Investigation, Resources, Writing—original draft. GEB: Conceptualization, Project administration, Supervision, Writing—review & editing. MCRO: Conceptualization, Project administration, Supervision, Writing—review & editing. MGB: Conceptualization, Project administration, Supervision, Writing—review & editing, Funding acquisition. All authors read and approved the submitted version.
All authors meet the authorship criteria as defined by the International Committee of Medical Journal Editors (ICMJE), declare that they have no conflicts of interest, and confirm that no related papers from the same study, nor any similar manuscripts, have been published elsewhere.
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Miguel Germán Borda was supported by the Norwegian Health Association. In addition, this paper represents independent research supported by the Norwegian government, through hospital owner Helse Vest (Western Norway Regional Health Authority). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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