Table 1 Basic characteristics of the included studies
From: Effect of prebiotics, probiotics, synbiotics on depression: results from a meta-analysis
Study | Country | Population (Diagnosis criteria) | Age Mean (SD) | Sex (%female) | Intervention | Control | Intervention duration | Follow-up period | Outcome measures |
|---|---|---|---|---|---|---|---|---|---|
Akkasheh, G., et al. (2016) [28] | Iran | MDD (DSM-IV and HDRS-17 ≥ 15) | Pro: 38.3 (12.1) Ct: 36.2 (8.2) | Pro:85.0 Ct: 85.0 | Probiotics (n = 20) | Placebo (n = 20) | 8 weeks | No | BDI |
Browne, P.D., et al. (2021) [29] | Netherlands | Pregnant woman with depressive symptoms (EPDS ≥ 10) | Pro: 29.7 (3.9) Ct: 31.7 (4.0) | Pro: 100 Ct: 100 | Probiotics (n = 20) | Placebo (n = 20) | 8 weeks | 4 weeks post-partum | EPDS |
Ghorbani, Z., et al. (2018) [30] | Iran | MDD (DSM-V and HDRS-17 of 17–23) | Syn: 34.5 (4.0) Ct: 35.5 (5.27) | Syn: 70.0 Ct: 70.0 | Synbiotics  + fluoxetine (n = 20) | Placebo  + fluoxetine (n = 20) | 6 weeks | No | HDRS |
Heidarzadeh-Rad, N., et al. (2020) [31] | Iran | MDD (clinical diagnosis of the psychiatrist) | Pro: 37.8 (7.9) Pre: 36.6 (8.4) Ct: 36.0 (8.5) | Pro: 71.4 Pre: 80.0 Ct: 60.0 | Probiotics (n = 28) or prebiotics (n = 25) + antidepressant medications | Placebo  + antidepressant medications (n = 25) | 8 weeks | No | BDI |
Huang, W., et al. (2019) [32] | China | MDD (ICD-10 + CCMD-3) | / | / | Probiotics  + electroacupuncture (n = 56) | Trimebutine maleate  + meptintin (n = 48) | 3 weeks | No | HDRS |
Iran | MDD (Clinical diagnosis of the psychiatry clinic) | Pro: 36.2 (7.9) Pre: 37.4 (8.0) Ct: 36.0 (8.5) | Pro: 71.1 Pre: 75.0 Ct: 66.7 | Probiotics (n = 38) Prebiotics (n = 36) | Placebo (n = 36) | 8 weeks | No | BDI | |
Reininghaus, E.Z., et al. (2020) [35] | Austria | Depressive episode (Interview M.I.N.I. by a psychiatric) | Pro: 43.0 (14.3) Ct: 40.1 (11.5) | Pro: 71.4 Ct: 81.8 | Probiotic  + pharmaceuticals (n = 28) | Placebo  + pharmaceuticals (n = 30) | 4 weeks | No | HDRS BDI |
Romijn, A.R., et al. (2017) [36] | New zealand | QIDS-SR16 ≥ 11 or DASS-42 ≥ 14 | Pro: 35.8 (14.0) Ct: 35.1(14.5) | Pro: 80.0 Ct: 76.9 | Probiotics (n = 40) | Placebo (n = 39) | 8 weeks | No | MADRS QIDS-SR16 DASS-42 |
Rudzki, L., et al. (2019) [37] | Poland | MDD (DSM-IV) | Pro:39.1(10.0) Ct: 38.9 (12.0) | Pro: 76.7 Ct: 66.7 | Probiotics  + SSRI (n = 30) | Placebo  + SSRI (n = 30) | 8 weeks | No | HDRS SCL-90 PSS-10 |
Schaub, A.C., et al. (2022) [38] | Switzerland | Depressive episode (ICD-10 or HDRS > 7) | Pro: 39.2 (11.5) Ct: 38.0 (10.2) | Pro: 73.7 Ct: 50.0 | Probiotics (n = 19) | Placebo (n = 24) | 4 weeks | 4 weeks after the intervention | HDRS BDI |
Tarutani, S., et al. (2022) [39] | Japan | MDD (ICD-10 and CGI < 5 and ≥ 2) | Pre: 54.3 (10.0) Ct: 53.4 (11.3) | Pre: 88.9 Ct: 81.8 | Prebiotics (n = 9) | Placebo (n = 11) | 24 weeks | No | MADRS |
Tian, P., et al. (2022) [40] | China | MDD (HDRS > 24) | Pro: 51.3(16.1) Ct: 48.2(14.0) | Pro: 70.0 Ct: 64.0 | Probiotics  + antidepressant medications (n = 20) | Placebo  + antidepressant medications (n = 25) | 4 weeks | No | HDRS MADRS BPRS |
Zhang, X., et al. (2021) [41] | China | Depression (DSM-5) | Pro: 45.8 (12.3) Ct: 49.7 (9.6) | Pro: 63.2 Ct: 64.5 | Probiotics  + antidepressant medications (n = 38) | Placebo  + antidepressant medications (n = 31) | 9 weeks | No | HDRS BDI |