Table 1.
Trial characteristics of single studies. A summary of the raw data as direction of change of the applied questionnaires are presented. It is questionnaire specific whether or not a decrease implies improvement or deterioration and accordingly, whether or not an increase implies improvement or deterioration. Psychiatric symptoms and CNS changes in the probiotic versus the placebo group: ↔: no statistical differences between the groups; ↓: significant reduction p < 0.05; ↓↓: significant reduction p < 0.01; ↓↓↓: significant reduction p < 0.001; ↑: significant increase p < 0.05; ↑↑: significant increase p < 0.01; A: analyzed; αLA: α-Lactalbumin; AUT: Austria; CAN: Canada; CFU: Colony forming unit; CHN: China; CN: Control group; CTG: Combined treatment group; DEU: Deutschland; DSM-5: American Diagnostic and Statistical Manual of Mental Disorders (5th Edition); DTG: Dietary treatment group (hypocaloric diet); ESP: Spain; FMS: Fibromyalgia; FRA: France; IRL: Ireland; IRN: Iran; ITA: Italy; IU: International Unit; JPN: Japan; KOR: Korea; LHFM: Lactobacillus helveticus-fermented milk; LP: Lactobacillus paracasei MCC1849; MCI: Mild cognitive impairment; MDD: Major depressive disorder; MYS: Malaysia; N: Number; NI: No intervention group; NLD: Netherlands; NR: Not reported; NWL: Normal weight lean; NWO: Normal weight obese; NZL: New Zealand; PL: Placebo group; POL: Poland; PR: Probiotic group; PRE: Prebiotic group; PreobOB: Pre-obese/obese; RCT: Randomized controlled trial; SEM: Standard error of mean; SE: Standard error; SD: Standard deviation; SSRI: Selective Serotonin Reuptake Inhibitor; SWE: Sweden; TWN: Taiwan; VAS: Visual Analog Scale. More explanations are provided in Table S2.
| Author (Year) | Country | Subject | Intake Length (Week) |
SampleSize (A); Sex (f%); AgeMean (SD); HealthCondition; Groups (N) | Probiotic Species (N); Dose; Times Intake per Day; Application | Outcomes |
|---|---|---|---|---|---|---|
| Akkasheh et al. (2016) [32] | IRN | Depression | 8 | 40 (40); f: 85%; age: PL→36.2 (8.2), PR→38.3 (12.1); MDD; groups: PL (20), PR (20) | Tak Gen Zist Pharmaceutical Company (3); each 2 × 109 CFU/g; 1/day; capsule | Behavioral: BDI ↓ |
| Adikari et al. (2020) [33] | MYS | Anxiety | 8 | 20 (19); f: 0%; age: PL→19 ± 0.66, PR→19 ± 0.81; healthy; groups: PL (9), PR (10) | Lactobacillus casei Shirota (1); 3 × 1010 CFU; 1/day; liquid | Neuropsychological: DVT reaction time ↓, accuracy percentage ↔ Neurophysiological: EEG ↔ (week 8), ↑ theta brain wave + delta brain wave for probiotic group (week 4); EDR ↔ |
| Allen et al. (2016) [34] | IRL | Stress | 8 | 27 (22); f: 0%; age: 25.5 (1.2); healthy; RCT Crossover : 4 weeks placebo, 4 weeks probiotics, no washout | Bifidobacterium longum 1714 (1); 1 × 109 CFU; 1/day; powder | Behavioral: Cohen PSS: ↓; STAI: ↔ Neuropsychological: PAL (total errors): ↔ Neurophysiological: EEG Mobility ↑, Cz theta power ↓ |
| Bagga et al. (2018) [19] | AUT | Emotional brain signatures | 4 | 45 (NR); f: 48.9%; age: PL→27.25 (5.78), PR→28.27 (4.2), NI→26.87 (4.97); healthy; groups: PL (15), PR (15), NI (15) | Ecologic 825 by Winclove Probiotics (9); 7.5 × 109 CFU/g; 1/day; powder | Behavioral: Post-hoc comparisons: PANAS ↑↑; SCL-90 ↔; ADS ↔; LEIDS: Subscales hopelessness ↓↓ and risk aversion ↓; PRP with less decision change for unpleasant stimuli ↑↑ RAU (response accuracy for unpleasant stimuli) Neurophysiological: fMRI BOLD contrast correlated with PANAS positive score ↑; Emotional decision-making task (neutral > baseline) contrast: significant differences (p value NR) in brain activity in left anterior cingulum compared to NI |
| Bagga et al. (2019) [18] | AUT | Functional connectivity in brain | 4 | 45 (NR); f: 51.1%; age: 26.24 (4.76); healthy; groups: PL (15), PR (15), CN (15) | Ecologic 825 by Winclove Probiotics (9); 7.5 × 106 CFU/g; 1/day; powder | Neurophysiological: significant changes in the functional connectivity (FC) comparing PRP with CON and PLP comparing to CON: ↑ Salience network in Cingulate gyrus + Precuneus cortex), ↓ Middle and superior frontal gyrus network in Frontal pole + Frontal medial cortex; comparing to PLP: ↓ Visual network in Postcentral gyrus + Precuneus and Default mode network in Frontal pole, Superior frontal gyrus + Paracingulate gyrus probiotic intervention did not influence the structural connectivity |
| Benton et al. (2007) [35] | UK | Mood and Cognition | 3 | 132 (126); f: 59.52%; age: 61.8 ± 7.3; healthy; groups: NR | Lactobacillus casei Shirota (1); 6.5 × 109 CFU; 1/day; liquid | Behavioral: POMS: ↔ Neuropsychological: Memory: Wechsler Memory scale, Retrieval from long-term memory, Test of verbal fluency: ↔; NART: converted to Z scores: ↔ |
| Chung et al. (2014) [36] | KOR | Cognitive Fatigue | 12 | 39 (36); f: 44.4%; age: 65.00 ± 4.14; >24 in MMSE-K; groups: PL (10), LHFM 500 mg (10), LHFM 1000 mg (7), LHFM 2000 mg (9) | Lactobacillus helveticus IDCC3801 (1); dose NR; 4/day; tablet | Behavioral: PSS ↔, GDS-SF ↔ Neuropsychological: DST, SRL, VLT, Serial 3 s and 7 s: ↔, RVIP: 1000 mg ↑ correct responses (post-hoc), ST: error responses 500 mg ↓ |
| De Lorenzo et al. (2017) [37] | ITA | Psychological Profile | 3 | 48 (48); f: 100%; age: NWL30.18 ± 2.04, NWO: 40.00 ± 12.54, PreobOB: 33.57 ± 10.57; healthy; groups: PL (24), PR (24); RCT Crossover: 3 weeks intervention, 3 weeks wash-out, 3 weeks other intervention | Biocult Strong, HOMEOSYN (9); each 1.5 × 1010 CFU/3 g; 1/day; powder | Behavioral: SCL90R: ↔; BUT ↓ (S) |
| Dickerson et al. (2014) [38] | USA | Schizophrenia | 14 | 65 (65); f: 35.4%; age: PL→48.1 (9.4), PR→44.4 (11.0); diagnosed schizophrenia with antipsychotic medication; groups: PL (32), PR (33) | Bifiform Balance (2); each 109 CFU; 1/day; tablet | Behavioral: PANSS ↔ |
| Dickerson et al. (2018) [39] | USA | Acute Mania | 24 | 66 (66); f: 63.6%; age: PL→33.3 (±13.3), PR→37.9 (±11.7); maniac episode; groups: PL (33), PR (33) | Chr. Hansen (2); >108 CFU; 1/day; tablet | Behavioral: YMRS, MADRS, BPRS ↔ |
| Diop et al. (2008) [40] | FRA | Stress | 3 | 75 (75); f: 72%; age: 38 ± 11; healthy; groups: PL (37), PR (38) | Probio stick (2); 3 × 109 CFU; 1/day; powder | Behavioral: Questionnaire assessing stress-induced symptoms (62 items) VAS 10 cm: ↓ abdominal pain, ↓ nausea/vomiting |
| Eskandarzadeh et al. (2021) [30] | IRN | Generalized Anxiety Disorder | 8 | 48 (39); f: 81.25%; age: PL→33.67 ± 6.56, PR→34.17 ± 6.14; GAD-7 score > 7; groups: PL (24), PR (24); Intake with sertraline in both groups | Takgene Zist Company (4); 1.8 × 1010 CFU; 1/day; capsule | Behavioral: HAM-A ↓↓, State-Anxiety score ↓, Trait-Anxiety score ↔, BAI ↔, WHO-QOL-BREF ↔ |
| Ghaderi et al. (2019) [41] | IRN | Schizophrenia | 12 | 60 (60); f: 6.7%; age: PL→43.2 ± 6.0, PR→44.8 ± 8.3; diagnosed schizophrenia; groups: PL (30), PR (30); probiotic group within take of 50,000 IU of Vitamin D3 every 2 weeks | Lacto Care (4); each 2 × 109 CFU; 1/day; capsule | Behavioral: PANSS ↓↓ in general and total subscore Neuropsychological: BPRS ↔ |
| Gualtieri et al. (2020) [42] | ITA | Anxiety | 12 | 142 (97); f: 61.9%; age: 41.29 (±14.9); healthy; groups: PL (71), PR (71) | Biocult Strong, HOMEOSYN (9); each 1.5 × 1010 CFU/3 g; 1/day; powder | Behavioral: HAM-A↓↓ (especially ↓ in IL-1β rs16944 carriers than in non-carrier), BUT ↔, SCL-90 ↔ |
| Ho et al. (2021) [43] | TWN | Depression | 4 (30 days) |
40 (40); f: 67.5%; age: PL→25.47 ± 4.64, PR→26.43 ± 5.95; PSQI > 5, ISI > 13; and met the DSM-5 criteria for chronic primary insomnia; group: PL (19), PR (21) | Lactobacillus plantarum PS128 (1); 3 × 1010 CFU; 2/day; capsule | Behavioral: BDI-II ↓, BAI ↔, PSQI ↔, ISI ↔, ESS ↔, VAS fatigued before sleep ↓↓ Neurophysiological: sleep EEG ↔ (During N1: theta power % ↓ at day 15) |
| Hwang et al. (2019) [44] | KOR | Mild Cognitive Impairment | 12 | 100 (100); f: 66%; age: PL→69.2 (7.00), PR→68.0 (5.12); healthy with MCI; groups: PL (50), PR (50) | DW2009 Lactobacillus plantarum C29 (1); 1.25 × 1010 CFU/g; 1/day; 2 capsules (800 mg) | Neuropsychological: VLT, ACPT, DST: ↑ combined cognitive function (subscore: Attention/Prefrontal function ↑ in composite score) |
| Inoue et al. (2018) [45] | JAP | Cognitive Function | 12 | 39 (38); f: 64.1%; age: 70.3 (±3.1); healthy; groups: PL (19), PR (20); intake with physical training | Morinaga Milk Industry Co., Ltd. (4); each 1.25 × 1010 CFU; 1/day; powder | Behavioral: PHQ-9 ↔, GAD-7 ↔ Neuropsychological: MoCA-J ↔ |
| Karbownik et al. (2020) [46] | POL | Stress | 4 | 92 (92); f: 60%; age: 22.6 ± 1.3; healthy; groups: PL (29), PR-Lactobacillus (32), PR-Saccharomyces (31) | LacidoEnter (1): 5 × 109; Dicoflor 60 (1): 6 × 109; 1/day; capsule | Behavioral: STAI ↔ Neuropsychological: Performance in Academic Examination ↔ |
| Kato-Kataoka et al. (2016) [47] | JAP | Stress | 8 | 49 (47); f: 44.9%; age: PL→22.8 (±0.3), PR→22.8 (±0.4); healthy; groups: PL (25), PR (24) | L.casei strain Shirota YIT 9029 (1); 1.0 × 1011 CFU; 1/day; liquid | Behavioral: feelings of stress by 100 mm VAS ↓, STAI ↔, NEO-FFI ↔ |
| Kazemi et al. (2019) [48] | IRN | Depression | 8 | 110 (110); f: 70.9%; age: 36.47 (8.03); mild to moderate major depression; groups: PL (36), PR (38), PRE (36) | Lallemand Health Solution (2); >10 × 109 CFU; 1/day; powder | Behavioral: BDI ↓ |
| Kelly et al. (2017) [49] | IRL | Stress and Cognitive Performance | 8 | 29 (NR); f: 0%; age: 24.59 (0.75); healthy; groups: PL-PR (15), PR-PL (14); RCT Crossover: switch of treatment after 4 weeks, no washout | Lactobacillus rhamnosus (JB-1) (1); 1 × 109 CFU; 1/day; capsule | Behavioral: BDI, BAI, PSS, STAI, SCL-90, PSQI, CCL: ↔ Neuropsychological: Test from CANTAB battery ↔; SECPT ↔ Neurophysiological: EEG ↔ |
| Kobayashi et al. (2019) [50] | JAP | Memory | 12 | 121 (117); f: 50.4%; age: PL→61.6 (6.37), PR→61.5 (6.83); subjective memory complaints and MMSE score 22–27; groups: PL (60), PR (61) | Bifidobacterium breve A1 (1); >1 × 1010 CFU; 1/day; capsule | Neuropsychological: RBANS ↔, MMSE ↔ |
| Lew et al. (2019) [51] | MYS | Stress, Anxiety, Memory, Cognition | 12 | 132 (103); f: 76.7%; age: PL→32.1 ± 11.4, PR→31.3 ± 10.8; healthy with score of moderate stress level on PSS-10; groups: PL (51), PR (52) | Lactobacillus plantarum P8 (1); 2 × 1010 CFU; 1/day; powder | Behavioral: PSS-10: ↔; DASS-42 total: ↓ week 4 + 12; DASS-42 stress: ↓ week 4, 8, 12; DASS-42 anxiety: ↓ week 4, 12; DASS-42 depression ↔ Neuropsychological: CBB speed for social emotional cognition (in women) ↓↓; international shopping list memory test ↑ |
| Messaoudi et al. (2011) [52] | FRA | Anxiety, depression, stress and coping | 4 (30 days) |
55 (55); f: 74.5%; age: PL→43.2 (8.5), PR→42.4 (7.5); score of <12 in the HADS-anxiety subscale and the HADS-depression subscale; groups: PL (29), PR (26) | Institut Rosell-Lallemand (2); 3 × 109 CFU; 1/day; powder | Behavioral: HSCL-90-GSI↓, HADS↓, HADS-A ↔, HADS-D ↔, PSS ↔, CCL ↔ |
| Mohammadi et al. (2016) [53] | IRN | mental health | 6 | 75 (70); f: 48.6%; age: PL→33.1 ± 6.1, PRyogurt→33.2 ± 6.4, PRcapsule→31.5 ± 5.8; healthy; groups: PL (20), PRyogurt (25), PRcapsule (25) | yogurt: Pegah Company (2), capsules: ZistTakhmir Co. (7); CFU: different, see Table S1; 1/day | Behavioral: GHQ ↔, DASS ↔ |
| Murata et al. (2018) [54] | JAP | Mood States | 12 | 241 (202); f: 100%; age: PL→20.2 ± 0.1, PR (10LP)→20.9 ± 0.5, PR (30LP)→21.1 ± 0.6; healthy; groups: PL (70), PR10LP (69), PR30LP (63) | LAC-Shield (1); 10PL: 1 × 1010 CFU, 30PL: 3 × 1010 CFU; 1/day; powder | Behavioral: POMS2 10LP group: ↓ T-scores for Friendliness week 6 + 12, ↓ T-scores for Vigour-Activity week 6 |
| Nishida et al. (2017) [55] | JAP | Stress, Sleep Quality | 5 | 32 (32); f: 34.4%; age: PL→21.31 ± 0.9, PR→34.4%; healthy; groups: PL (16), PR (16) | heat-inactivated Lactobacillus gasseri CP2305 (1); 1 × 1010 CFU; 1/day; liquid | Behavioural: GHQ-28 total score ↔, ↑ somatic symptom score, significant interaction of treatment and sex; Zung-SDS ↔; HADS ↔; STAI ↔; PSQI ↔ |
| Nishida et al. (2019) [56] | JAP | Stress | 24 | 60 (NR); f: 31.7%; age: PL→25.3 ± 0.6, PR→24.9 ± 0.5; healthy; groups: PL (31), PR (29) | Lactobacillus gasseri CP2305 (1); 1 × 1010 bacterial cells; 2 tablets 1/day | Behavioral: STAI-state ↔, STAI-trait ↓; GHQ28 total ↔, depression ↓; HADS ↔; PSQI ↓ Neurophysiological: EEG: REM and non-REM sleep times ↔, total delta power ↔, ↑ ration of EEG delta power in the first sleep cycle, ↓ sleep latency of the first N3 stage and wake time after sleep onset |
| Nishihira et al. (2014) [57] | JAP | Stress | 12 | 238 (224); f: 69.2%; age: PL→54.25 ± 10.93, PR→53.61 ± 11.31; healthy; groups: PL (109), PR (115) | MegMilk Snow Brand Co. Ltd. (2); SBT2055 > 5 × 108 CFU, SBT2928 > 1 × 109 CFU; 1/day; yogurt | Behavioral: GHQ-28 ↔ |
| Ohsawa et al. (2018) [58] | JAP | Cognitive Function | 8 | 61 (60); f: 56.7%; age: PL→57.8 ± 5.9, PR→58.5 ± 6.5; healthy, baseline RBANS total score 29–52; groups: PL (29), PR (31) | Lactobacillus helveticus CM4 (1); dose: NR; 1/day; liquid | Behavioral: POMS ↔ Neuropsychological: RBANS total ↔, five index scores: ↑ attention score, subtest index score: ↑ Coding |
| Östlund-Lagerström et al. (2016) [59] | SWE | Wellbeing | 12 | 290 (249); f: PR→57%, PL→65.6%; age: PR→72.6 (5.8), PL→72 (5.6); mentally and physically fit; groups: PL (124), PR (125) | Lactobacillus reuteri DSM 17938 (1); 1 × 108 CFU; 2/day; powder | Behavioral: HADS ↔,PSS ↔ |
| Papalini et al. (2019) [20] | NLD | Neurocognition | 4 (28 days) |
61 (58); f: 100%; age: PL→22 (SEM: 0.5), PR→21 (SEM: 0.4); healthy; groups: PL (29), PR (29) | Ecologic Barrier (9); 5 × 109 CFU; 1/day; powder | Behavioral: BDI ↔, LEIDS-r ↔, BIS-BAS ↔ Neuropsychological: SECPT↔; Digit Span Test ↔, Emotional face-matching paradigm ↔, Emotional face-word stroop paradigm ↔, Classic colour-word stroop paradigm↔ Neurophysiological: fMRI ↔ |
| Patterson et al. (2020) [60] | DEU | Stress, Anxiety | 5 | 120 (117); f: 49.6%; age: PL→23.25 (4.20), PR→23.73 (4.27); healthy; groups: PL (59), PR (58) | Lacticaseibacillus paracasei Lpc-37 (1); 1.75 × 1010 CFU; 1/day; capsule | Behavioral: STAI ↔, VAS Stress ↔, VAS Insecurity ↔ (↓male), VAS Anxiety ↔ (↓male), VAS Exhaustion ↔, PSS ↔ (↑ female), BAI ↔, DASS-24 ↔, Online Diary ↔ (Perceived Productivity + Perceived Health Status ↑ and Sleep Related Recovery ↑↑ in high chronic stress subgroup) |
| Rao et al. (2009) [61] | CAN | Chronic Fatigue Syndrome | 8 | 39 (35); f: 77.1%; age: 18–65; healthy, diagnostic criteria for CFS; groups: PL (16), PR (19) | Lactobacillus casei strain Shirota (1); 8 × 109 CFU; 3/day; powder | Behavioral: BDI ↔, BAI ↓ |
| Raygan et al. (2018) [62] | IRN | Mental health | 12 | 60 (60); f: 50%; age: PL→67.3 ± 11.0, PR→71.5 ± 10.9; diagnosed with type 2 diabetic and coronary heart disease (2–3 vessel); groups: PL (30), PR (30); Intervention Group with 50,000 IU vitamin D every 2 weeks | LactoCare (4); 8 × 109 CFU; 1/day; application: NR | Behavioral: BDI ↓↓, BAI ↓↓, GHQ-28 ↓↓ |
| Raygan et al. (2019) [63] | IRN | Mental health | 12 | 60 (54); f: 61.1%; age: PL→62.4 ± 13.1, PR→64.8 ± 8.3; diagnosed with type 2 diabetic and coronary heart disease (2–3 vessel); groups: PL (27), PR (27); Intervention Group with 200 µg/day selenium | LactoCare (4); 8 × 109 CFU; 1/day; application: NR | Behavioral: BDI ↓↓, BAI ↓, PSQI ↔ |
| Reininghaus et al.(2020) [64] | AUT | Depression | 4 (28 days) | 82 (61); f: 77.0%; age: PL→40.11 (11.45), PR→43.00 (14.31); depressive episode by MINI; groups: PL (33), PR (28); bothgroups: 125 mg (D-Biotin) Vitamin D7 | OMNi-BiOTiC Stress Repair (9); 7.5 × 109 CFU; 1/day; powder | Behavioral: HAMD, BDI-II, SCL-90R, MSS, GLQI: ↔ |
| Roman et al. (2018) [65] | ESP | Fibromyalgia | 8 | 40 (31); f: 92.5%; age: PL→50.27 ± 7.86, PR→55.00 ± 8.37; diagnosed with FMS; groups: PL (20), PR (20) | ERGYPHILUS Plus (4); 6 × 106 CFU; 4/day; capsule | Behavioral: STAI ↔, BDI ↔ Neuropsychological: MMSE ↔, two-choice task ↓, IGT ↔ |
| Romijn et al. (2017) [66] | NZL | Depression | 8 | 79 (79); f: 78.5%; age: PL→35.1 (14.5), PR→35.8 (14); healthy; ≥11 on QIDS-SR16 or ≥14 on DASS-42; groups: PL (39), PR (40) | Lallemand Health Solution (2); ≥ 3 × 109 CFU; 1/day; powder | Behavioral: MADRS, iCGI, QIDS-SR16, GAF, DASS-42: ↔ |
| Rudzki et al. (2019) [67] | POL | Depression | 8 | 79 (60); f: 71.7%; age: PL→38.9 (12), PR→39.13 (9.96); major depression during SSRI monotherapy or drug free; groups: PL (39), PR (40); with SSRI treatment | Sanprobi IBS (1); 10 × 109 CFU; 2/day; capsule | Behavioral: HAM-D 17 ↔, SCL-90 ↔, PSS-10 ↔ Neuropsychological: APT ↑↑, Stroop Test A + B ↔, RFFT ↔, TMT A + B ↔, CVLT ↑ |
| Sanchez et al. (2017) [68] | CAN | Depression, Anxiety and Stress | 24 | 126 (125); f: 61.6%; age: PL→37 ± 10, PR→35 ± 10; BMI between 29 and 41kg/m; groups: PL (63), PR (62) | Lactobacillus rhamnosus CGMCC1.3724 (1); 3.24 × 108 CFU/day; 2/day; capsules | Behavioral: BDI ↓, STAI ↔, PSS ↔ |
| Sashihara et al. (2013) [69] | JAP | Mental Condition | 4 | 44 (44); f: 0%; age: PL→20.2 ± 1.1, PR+αLA→19.9 ± 0.9, PR→19.8 ± 0.9; engaged in high-intensity training ≥5 days/week; groups: PL (14), PR (15), PR+αLA (15) | Lactobacillus gasseri OLL2809 (1); 1 × 1010 CFU; 2 tablets 3/day | Behavioral: POMS and VAS for fatigue ↔ |
| Sawada et al. (2017) [70] | JAP | Mental and Sleep Quality | 4 | 24 (NR); f: 0%; age: NR; healthy; RCTCrossover; group1: placebo (4 weeks), washout (3 weeks), probiotic (4 weeks), group2: probiotic (4 weeks), washout (3 weeks), placebo (4 weeks) | Lactobacillus gasseri CP2305 (1); 1 × 1010 CFU; 1/day; powder | Behavioral: GHQ28 ↔, Zung-SDS ↔, HADS depression + anxiety ↓, STAI state ↓, PSQI global + disturbance score ↓ |
| Severance et al. (2017) [71] | USA | Schizophrenia | 14 | 65 (56); f: 33.9%; age: PL→48.11 ± 9.6, PR→44.66 ± 11.4; diagnosis of schizophrenia or schizoaffective disorder; groups: PL (26), PR (30) | Bifiform Balance (2); each 109 CFU; 1/day; application: NR | Behavioral: PANSS ↔ |
| Shinkai et al. (2013) [72] | JAP | Mood and Quality of Life | 20 | 300 (278); f: 50.4%; age: PL→70.9 ± 2.7, PRlowdose→71.0 ± 4, PRhighdose→70.8 ± 3.4; healthy; groups: PL (93), PRlowdose (92), PRhighdose (93) | Lactobacillus pentosus strain b240 (1); low-dose: 2 × 109 CFU, high dose: 2 × 1010 CFU; 1/day; tablets | Behavioral: POMS ↔, SF-36 ↓ |
| Steenbergen et al. (2015) [73] | NLD | Sad Mood | 4 | 40 (NR); f: 80%; age: PL→19.7 (1.7), PR→20.2 (2.4); healthy; groups: PL (20), PR (20) | Ecologic Barrier (8); 2.5 × 109 CFU/g; 1/day; powder | Behavioral: LEIDS-r total ↓↓↓: aggression ↓↓; rumination ↓↓↓; BDI II ↔; BAI ↔ |
| Takada et al. (2016) [74] | JAP | Stress | 8 | 149 (140); f: 45.7%; age: PL→22.8 ± 0.2, PR→23.0 ± 0.2; healthy; groups: PL (70), PR (70) | Lactobacillus casei YIT 9029 (1); 1 × 109 CFU/mL; liquid (100 mL); 1/day | Behavioral: STAI ↔ |
| Takada et al. (2017) [75] | JAP | Stress and Sleep | 11 | 98 (94); f: 41.5%; age: PL→22.6 ± 0.2, PR→22.8 ± 0.2; healthy; groups: PL (48), PR (50) | L. casei strain Shirota YIT 9029 (1); 1 × 109 CFU/mL; 100 mL liquid; 1/day | Behavioral: GHQ ↔; NEO-FFI ↔; STAI ↔; PSQI ↔; total OSA ↔; subdivided factors (subsequently compared): sleepiness on rising ↑, sleep length↑↑ Neurophysiological: Sleep EEG: WASO ↑; N3 sleep ↓↓ |
| Tillisch et al. (2013) [21] | USA | Brain Activity | 4 | 36 (NR); f: 100%; age: 30 ± 10.4; healthy; groups: PL (11), PR (12), NI (13) | Danone Research facilities (4);dose: different, see Table S1; 2/day; liquid | Behavioral: Diary mood symptoms ↔; HAD ↔ Neurophysiological: Neuroimaging Acquisition and Analysis fMRI ↓↓↓ BOLD activity in the primary viscerosensory and somatosensory cortices |
| Tran et al. (2019) [76] | USA | Anxiety | 4 (28 days) |
90 (68); f: 75.6%; age: 20.59 (2.65); healthy; ConditionA (17): highCFU[50billion] + high species count [18], ConditionB (19): highCFU[50billion] + low species count [10], ConditionC (16): control/placebo group, ConditionD (19): lowCFU[15billion]+high species count[18], ConditionE (19): lowCFU[10billion]+low species count [10] | commercially available as over-the-counter products (e.g., Amazon) (from 10 till 20); 1 × 1010–5 × 1010 CFU; 1/day; pills | Behavioural: BAI, ACQ-R, PANAS, NMR, PSWQ ↔ |
| Wang et al. (2019) [22] | DEU | Stress | 4 | 43 (40); f: 65%; age: PL→33.00 ± 2.83, PR→31.00 ± 2.28; healthy; groups: PL (20), PR (20) | Bifidobacterium longum 1714 (1); 1 × 109 CFU; 1/day; powder | Behavioural: SF-36↔ Neurophysiological: resting state MEG: ↑ theta band power, ↓ beta-3 band power in different brain region; during social distress: ↑ (S) theta band power,↑ alpha band power in different brain region; in both conditions’ inclusion/exclusion; NTS ↔; SEP ↔; MQ ↔ |
| Xiao et al. (2020) [77] | JAP | Memory | 16 | 80 (80); f: 51.3%; age: PL→60.9 (6.9), PR→61.3 (7.7); MMSE score 22 or more; group: PL (40), PR (40) | Bifidobacterium breve A1 (1); 1 × 1010 CFU; 1/day; capsule | Neuropsychological: RBANS ↓↓↓ in RBANS total score, Immediate memory, Visuospatial/Constructional, Delayed memory; JMCIS ↔ |
| Yamamura et al. (2009) [78] | JAP | Sleep | 3 | 30 (29); f: 20.7%; age: PL→70.6 ± 5.65, PR→72.14 ± 5.67; healthy, no use of substances that influence sleep; groups: PLfirst (15), PRfirst (14); RCT Crossover→placebo first group: placebo (3 weeks), washout (3 weeks), probiotic (3 weeks), probiotic first group: probiotic (3 weeks), washout (3 weeks), placebo (3 weeks) | Lactobacillus helveticus strain CM4 (1); dose: NR; 1/day; liquid | Behavioural: SHRI ↔, SF-36 ↔ Neurophysiological: Actigraphy ↔ |
| Zhang et al. (2021) [79] | CHN | Depression | 9 | 82 (69); f: 63.8%; age: PL→49.7 ± 9.6, PR→45.8 ± 12.3; diagnosed depression (DSM-5); groups: PL (31), PR (38) | Lacticaseibacillus paracasei YIT 9029 (strain Shirota: LcS) (1); 1.0 × 1010 CFU; 1/day; liquid | Behavioural: BDI, HAMD: decreased significantly in both groups, no comparison between groups |