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. 2024 Apr 30;16(9):1352. doi: 10.3390/nu16091352

Table 1.

Synthesis of the studies included in this systematic review.

Author, Year Subjects (I/C) Diagnosis Average Age (Years) Sex (%female) Psychobiotic (Form; Dose) Treatment Duration (Weeks) Evaluated Outcome Depression Scale Used Conclusion
Tian et al., 2022 [34] I: 20
C: 25
Depression 51.3 67 Freeze-dried powder; B. breve CCFM1025 1010 UFC 4 Improvement in depression score BPRS, MADRS, HDRS-24 CCFM1025 is a promising psychobiotic that mitigates depression and associated gastrointestinal disorders.
Chahwan et al., 2019 [35] I: 34
C:37
Depression 36.6 70 Freeze-dried powder; Ecologic ®Barrier 2.5 × 109 UFC/g 8 Improvement in depression score BDI-II The consumption of probiotics can induce changes in cognitive patterns associated with depression.
Reininghaus et al., 2020 [36] I:28
C:33
Depression 43 77 Freeze-dried powder; OMNi-BiOTiC® Stress Repair 7.5 × 109 organisms +125 mg of vitamin B7 4 Improvement of psychiatric symptoms HDRS, BDI-II Both groups significantly improved over time in psychiatric symptoms. However, there were no significant differences between groups in the scores of the scales used.
Kazemi et al., 2019 [37] I1:38
I2:36
C:36
Depression 36.1 69 Freeze-dried powder; L. helveticus R0052, B. longum R0175 10 × 109 UFC or Galactosaccharide 8 Improvement in depression score BDI Probiotic supplements in people with depression resulted in an improvement in the BDI score compared to placebo, while no significant effect was observed when prebiotics were used.
Romijn et al., 2017 [38] I:40
C:39
Depression 35.8 78 Freeze-dried powder; L. helveticus R0052 and B. longum R0175 3 × 109 UFC/day 8 Improvement in the scores of the scales used MADRS, DASS-42, QIDS-SR16 Prescribing probiotics is not effective for treating low mood. The lack of observed effect on symptoms may be due to the severity, chronicity, or resistance to treatment of the sample.
Sacarello et al., 2020 [39] I:45
C:44
Depression 48.6 73 Tablet; SAME 200 mg and L. plantarum HEAL9 1 × 10⁹ UFC/day 6 Improvement in depression score Z-SDS The combination of SAMe and L. plantarum HEAL9 in adults with mild to moderate depression symptoms produced clinically significant effects after 2 weeks.
Nikolova et al., 2023 [40] I:24
C:25
Depression 32.5 80 Multispecies probiotic capsule (14 strain) with 2 × 109 UFC. 4 capsules/day 8 Improvement in depression score HDRS-17, HAMA Depressive symptoms improved in both groups, with a more significant reduction in the probiotic group from week 4. On the other hand, overall, the treatment was well tolerated.
Zhang et al., 2021 [41] I:38
C:31
Depression 45.8 63.7 Drink; L. paracasei strain Shirota 1 × 1010 CFU/mL/day 9 Improvement in depression score HDRS, BDI HDRS and BDI scores significantly decreased. The degree of depression improved in both the placebo and intervention groups; however, there were no significant differences between groups.
Akkasheh et al., 2016 [42] I:17
C:18
Depression 38.3 85 Capsule; L. acidophilus 2 × 109 CFU/g, L. casei 2 × 109 CFU/g, and B. bifidum 2 × 109 CFU/g/day 8 Improvement in depression score BDI After 8 weeks of intervention, patients who received probiotic supplements had a significantly lower total BDI score.
Schneider et al., 2023 [43] I:30
C:30
Depression 38 60 Drink; Vivomix® 900 × 109 CFU/day 4 Improvement of cognitive symptoms VLMT Additional supplementation with probiotics improves verbal episodic memory and affects the neuronal mechanisms underlying cognitive impairment in depression.
Ullah H et al., 2022 [44] I:36
C:32
Depression 39 58.4 L. helveticus Rosell®-52, B. longum Rosell®-175, 3 × 109 CFU/day, vitamina B6 1.70 mg and SAME 200 mg/day 12 Improvement in depression score HDRS, PHQ-9 Daily intake of SAMe and probiotic is effective in improving symptoms and quality of life in subjects with subthreshold depression and mild to moderate depression.
Tarutani S et al., 2022 [45] I:9
C:11
Depression 53 85 Syrup; 4G-beta-D-galactosylsucrose 3.2 g 24 Improvement in depression score MADRS Intake of the prebiotic can improve self-efficacy, but not depressive symptoms, even in a small sample.
Vaghef E et al., 2021 [46] I:22
C:23
Depression 37.4 NR Freeze-dried powder; inulin 10 g/day 8 Improvement in depression score HDRS, BDI-II The use of prebiotic for 8 weeks does not significantly improve depression symptoms compared to the placebo group.
Vaghef E et al., 2023 [47] I:22
C:23
Depression 38.5 NR Freeze-dried powder; inulina 10 g/day 8 Improvement of symptoms HDRS In the short term, supplementation with prebiotics had no significant beneficial effects on depressive symptoms.
Majeed M et al., 2018 [48] I:20
C:20
Depression 43.8 85 Tablets; B. coagulans MTCC 5856 2 × 109 CFU/day 12 Improvement in depression score HDRS, MADRS, CES-D The probiotic showed solid efficacy in treating patients experiencing symptoms of irritable bowel syndrome with major depressive disorder.
Ghorbani Z et al., 2018 [49] I:20
C:20
Depression 34.4 70 Capsule; Familact H® 500 mg 2 capsules/day 6 Improvement in depression score HDRS-17 The symbiotic group had a significantly lower HAM-D score compared to the placebo.
Miyaoka T et al., 2018 [50] I:20
C:20
Depression 44.2 60 Tablets; C.
butyricum MIYAIRI 588 60 mg/day
8 Improvement of symptoms HDRS-17, BDI The administration of probiotic in combination with antidepressants significantly improves symptoms of depression.
Kazemi A et al., 2018 [51] I1:38
I2:36
C:36
Depression 36.7 71 Freeze-dried powder; L. helveticus R0052 and B. longum R0175 10 × 109 CFU/day; or galactooligosaccharide 8 Improvement in depression score BDI-II A beneficial effect of probiotics on the remission of depression was observed, as evidenced by an improvement in the BDI score. However, probiotics had no effect on the levels of circulating pro-inflammatory cytokines.
Tian P et al., 2023 [52] I:15
C:13
Depression 38.8 NR Freeze-dried powder; B. breve CCFM1025, B. longum CCFM687, and P. acidilactici CCFM6432 4 × 109 CFU/g 4 Improvement in depression score HDRS, MADRS, BPRS Probiotic treatments can significantly mitigate psychiatric symptoms and comorbid gastrointestinal symptoms in patients with major depressive disorder.
Mohsenpour M et al., 2023 [53] I:40
C:40
Depression 42.2 56 Drink; milk kefir tablets 500 cc/day 8 Improvement in depression score BDI-II The BDI-II score was reduced in both study arms; however, the comparison between groups was not statistically significant.
Komorniak N et al., 2023 [54] I:21
C:17
Depression 44.9 NR Capsule; Sanprobi Barrier® 4 capsules 2 × 109 CFU/day 5 Improvement in depression score HDRS, BDI An improvement in mental functioning of patients (reduction of BDI and HDRS) was evidenced, but it was not related to the probiotic used.
Baião R et al., 2023 [55] I:35
C:36
Depression 27.9 63.4 Capsule; Bio-Kult® 2 × 109 CFU 4 Improvement of emotional processes STAI, PHQ-9, ETB The intake of probiotics decreased depression scores but did not correlate with changes in emotional processing.
Mahboobi S et al., 2022 [56] I:39
C:35
Depression 38.9 78 Capsule; Probio-Tec® BG-VCap-6.5 at 1.8 × 1010 CFU + Magnesium chloride 500 mg. 2 capsules/day 9 Improvement in depression score BDI-II The administration of probiotic plus magnesium had no significant effects on mood, cognition, and intestinal integrity in individuals with obesity and depressed mood.
Kreuzer K et al., 2022 [57] I:28
C:29
Depression 44.6 73.6 Freeze-dried powder; OMNi-BiOTiC® Stress Repair 7.5 × 109 organisms + vitamina B7 4 Improvement in depression score HDRS, BDI-II Both groups significantly improved in depression scores over time. However, no differences between groups were reported.
Xiao et al., 2020 [58] I:40
C:39
Cognitive impairment 61.3 51 Capsule; B. breve A1, 1 × 1010 CFU 2 capsules/day 16 Improvement in RBANS score RBANS The total RBANS score significantly improved in the probiotic group after 16 weeks of consumption, particularly in the immediate memory and visuospatial/constructive domain.
Sakurai et al., 2022 [59] I:39
C:39
Cognitive impairment 76.8 54 Freeze-dried powder; L. plantarum OLL2712 at 5 × 109/day 12 Improvement in memory score MPI, VIM, and VBM Older adults who consumed the probiotic showed significant improvement in composite memory and visual memory compared to the placebo group.
Asaoka et al., 2022 [60] I:55
C:60
Cognitive impairment 77.2 56 Freeze-dried powder; B. breve MCC1274 2 × 1010 CFU/day 24 Improvement in cognition ADAS-Jcog and MMSE According to the ADAS-Jcog subscale, orientation significantly improved compared to placebo at 24 weeks.
Hwang Y et al., 2019 [61] I:50
C:50
Cognitive impairment 69.2 66 Capsule; fermented soy with L. plantarum C29 800 mg/day 12 Effects on cognition VLMT, ACPT Compared to the placebo group, the group that was administered probiotics showed greater improvements in combined cognitive functions, especially in the attention domain.
Kobayashi Y et al., 2019 [62] I:61
C:60
Cognitive impairment 61.5 49.5 Capsule; B. breve A1 >2 × 1010 2 capsules /day 12 Effects on cognition RBANS, MMSE At 12 weeks, neuropsychological test scores increased in subjects who consumed probiotic or placebo; however, no significant differences between groups were observed.
Ghaderi A et al., 2019 [63] I:30
C:30
Schizophrenia 44.8 6 Tablet; probiotic 8 × 109 CFU/day of L. acidophilus, B. bifidum, L. reuteri and L. fermentum (each one 2 × 109) and 50,000 IU of vitamin D3 every 2 weeks 12 Improvement of symptoms PANSS The administration of probiotics plus vitamin D for schizophrenia for 12 weeks chronically had beneficial effects on the PANSS score.
Jamilian H et al., 2021 [64] I:26
C:25
Schizophrenia 43.9 NR Capsule; LactoCare® 8 × 109 CFU/day plus selenium 200 μg/day 12 Improvement of symptoms PANSS Co-supplementation with probiotics and selenium for 12 weeks in patients with chronic schizophrenia had beneficial effects on the overall PANSS score.
Tomasik J et al., 2015 [65] I:30
C:27
Schizophrenia 44.8 35 Tablet; L. rhamnosus strain GG 109 CFU and B. animalis subsp. lactis strain Bb12 109 CFU/1 tablet/day 14 Effect on schizophrenia symptoms PANSS The provided probiotics had immunomodulatory effects, affecting molecules unresponsive to standard antipsychotic therapy. However, it did not reduce psychotic symptoms.
Soleimani et al., 2023 [66] I:31
C:31
Schizophrenia 34.7 37 Capsule; FamiLact® Lactobacilo 9 × 109, Bifidobacteria 1.25 × 1010, and S. Salivarius 1.5 × 1010/day 12 Improvement of symptoms BPRS, PANSS Adding probiotics to oral antipsychotics did not improve psychiatric symptoms as measured through BPRS or PANSS.
Dickerson F et al., 2014 [67] I:33
C:32
Schizophrenia 44.4 42 Tablet; L. rhamnosus strain GG 109 CFU, B. animalis subsp. lactis Sib12 × 109 CFU 14 Improvement of symptoms PANSS No significant differences were shown in the total PANSS score between probiotic supplementation and placebo.
Zeng C et al., 2022 [68] I:21
C:21
TAB I 22.2 NR Capsule; Bifidobacterium, Lactobacillus, and Enterococcus 1 × 107 CFU, 6 capsules/day 12 Improvement of symptoms YMRS, HAMA-14, HDRS The symptom of mania was significantly alleviated in patients who received probiotic supplements compared to the placebo group.
ShahrbabakiM et al., 2020 [69] I:19
C:19
TAB I 38.9 NR Capsule; B. bifidum, B. lactis, B. langum, and L. acidophilus 1.8 × 109 CFU, 1 capsule/day 8 Improvement of symptoms YMRS, HDRS-17 Mania symptoms were significantly alleviated in patients who received probiotic supplements compared to the placebo group.
Dickerson F et al., 2018 [70] I:26
C:26
TAB I 37.9 63 L. rhamnosus strain GG and B. animalis subsp. lactis strain Bb12 > 108 CFU 24 Prevention of rehospitalizations NR The consumption of probiotics had no significant effects on the improvement and treatment of patients with bipolar disorder type 1.
Zhang J et al., 2023 [71] I:46
C:44
TAB I-depressive 20.4 56 Freeze-dried powder; B. animalis subsp. lactis BAMA-B06/BAu-B0111, 1 × 109 CFU/g–2 g/day 4 Improvement in depression score HDRS-17, HAM-A-14 The use of probiotics is associated with a lower rate of rehospitalization in patients recently discharged after hospitalization for mania.
Gualtieri et al., 2020 [72] I:65
C:32
Anxiety 43.8 61.9 Multispecies probiotic oral suspension ** 3 g/day. 12 Improvement in HAM-A score HAM-A Adjunctive therapy with probiotics may enhance the efficacy of conventional medications for bipolar I disorder, producing a favorable evolution of emotional state.
Eskandarzadeh S et al., 2021 [73] I:24
C:24
Anxiety 34.1 81 Capsule; B. longom, B. bifidum, B. lactis, and L. acidophilus 18 × 109 and sertraline 25 mg 8 Effects on severity of symptoms HAM-A, BAI The use of probiotic was associated with a decrease in the HAM-A scale score.
Pinto et al., 2017 [74] I: 22
C: 22
Depression and anxiety 46.5 54.5 Freeze-dried powder; B. longum NCC3001 1010 CFU 6 Improvement in anxiety and depression score HADS The intake of the probiotic improved cognitive functions compared to placebo, in addition to aspects of mood and sleep.
Schaub et al., 2022 [75] I:21
C:26
Depression and anxiety 39.4 57 Drink; Vivomix® 90 × 109 CFU/day 4 Improvement in anxiety and depression score HDRS, BDI, STAI The administration of the psychobiotic had beneficial effects on mild and moderate depression, improves quality of life, but does not reduce anxiety.
Zhu et al., 2023 [76] I:30
C:60
Depression and anxiety 22 50 Freeze-dried powder; L. plantarum JYLP326 1.5 × 1010 CFU 2 times per day 3 Improvement in anxiety and depression score HAMA-14, HDRS Supplementary treatment with probiotics improves depressive symptoms and maintains a healthy enterotype.
Rudzki et al., 2018 [77] I:30
C:30
Depression and anxiety 39 71.6 Capsule; Lactobacillus Plantarum 299v 10 × 109 CFU 2 times per + ISSR 8 Improvement in depression, anxiety, and cognition score HDRS, SCL-90, PSS-10 The administration of the probiotic JYLP-326 could significantly alleviate anxiety/depression symptoms and insomnia in university students anxious about exams.
Moludi et al., 2022 [78] I:66
C:22
Depression and anxiety 51.2 39.5 Capsule; L. Rhamnosus 1.9 × 109 and inulin 15 g/day 8 Improvement in anxiety and depression score BDI, STAI The administration of probiotic improved cognitive function in patients; however, there were no significant differences in the scores obtained from the HDRS and SCL-90 scales.
Haghighat N et al., 2021 [79] I1:25
I2:25
C:25
Depression and anxiety 47 52 Capsule; synbiotic (15 g of prebiotics, 5 g of probiotic containing L. acidophilus T16, B. bifidum BIA-6, B. lactis BIA-7, and B. longum BIA-8 (2.7 × 107 CFU/g each)) or probiotics (5 g of probiotics as in the synbiotic group) 4 times/day 12 Improvement in anxiety and depression score HAD Co-supplementation of probiotics and inulin for 8 weeks in patients with coronary artery disease produced benefits on depression, anxiety, and inflammatory biomarkers.
Regiada L et al., 2021 [80] I1:27
I2:28
I3:26
C:25
Depression and anxiety 22.2 100 Capsules; probiotic composed of Lactobacilllus 20 × 109 CFU (L. acidophilus, L. plantarum, L. gasseri, L. paracasei, L. bulgaricus, L. brevis, L. casei, L. rhamnosus, L. salivaruys) Bifidobacteria 10 billion CFU (B. lactis, B. bifidum, B. breve, B. infantis, B. longum); 1 capsule/day; or Probiotic + omega-3 200 mg/day; or omega-3 200 mg/day 12 Improvement in symptoms of depression, anxiety, and stress BDI-II, STAI, PSS-10 12 weeks of supplementation with synbiotics produced an improvement in depression symptoms compared to probiotic supplementation in patients on hemodialysis.
Freijy T et al., 2023 [81] I1:31
I2:28
I3:32
C:28
Depression, anxiety, and stress 36.3 91 Capsule; BioCeuticals® 12 × 109 CFU 2 times/day; or probiotic-rich diet 5 g/day; or combination of both (synbiotic) 8 Improvement in mood, depression, and anxiety score BDI-II, pss-10, BAI Omega-3, a probiotic, or a combination of both supplements did not reduce psychological symptoms in a sample of women in a non-clinical setting, compared to a placebo supplement.
Chong et al., 2019 [82] I:56
C:55
Anxiety and stress 31.1 NR Freeze-dried powder; L. plantarum DR7 1 × 10 9 CFU/day 12 Improvement in anxiety, stress, memory, and cognitive function PSS-10, DASS-42 A dietary intervention rich in prebiotics improves mood, anxiety, stress, and sleep in adults with moderate psychological distress and low prebiotic intake. A symbiotic combination does not appear to have a beneficial effect on mental health outcomes.
Lew et al., 2019 [83] I:52
C_51
Anxiety and stress 31.3 77 Freeze-dried powder; L. plantarum P8 2 × 1010 CFU/ day 12 Improvement in anxiety, stress, memory, and cognitive function PSS-10, DASS-42 The probiotic reduced symptoms of stress and anxiety, accompanied by an improvement in cognitive function and memory.
Wu SI et al., 2022 [84] I:33
C:32
Anxiety and stress 35.3 98 Capsule; HK-PS23 (300 mg de L. paracasei PS23) 8 Improvement in anxiety score PSS-10, STAI The probiotic reduced stress and anxiety symptoms through anti-inflammatory properties, followed by an improvement in memory and cognitive abilities.

I/C: Intervention/Control; %f: percentage of women. CFU: Colony Forming Units. BPRS: Brief Psychiatric Rating Scale. BDI-II: Beck Depression Inventory. MADRS: Montgomery–Åsberg Depression Rating Scale. HDRS-24: Hamilton Depression Rating Scale. HADS: Hospital Anxiety and Depression Scale. Ecologic®Barrier: consists of 9 strains Bifidobacterium bifidum W23, Bifidobacterium lactis W51, Bifidobacterium lactis W52, L. acidophilus W37, Lactobacillus brevis W63, Lactobacillus casei W56, Lactobacillus salivarius W24, Lactococcus lactis W19, and Lactococcus lactis W58 (total cell count 1 × 1010 CFU/day). Vivomixx®: contains Streptococcus thermophilus NCIMB 30438, Bifidobacterium breve NCIMB 30441, Bifidobacterium longum NCIMB 30435 (reclassified as B. lactis), Bifidobacterium infantis NCIMB 30436 (reclassified as B. lactis), Lactobacillus acidophilus NCIMB 30442, Lactobacillus plantarum NCIMB 30437, Lactobacillus paracasei NCIMB 30439, Lactobacillus delbrueckii subsp. Bulgaricus NCIMB 30440. STAI: State-Trait Anxiety Inventory. OMNi-BiOTiC® Stress Repair: B. bifidum W23, B. lactis W51, B. lactis W52, L. acidophilus W22, L. casei W56, L. paracasei W20, L. plantarum W62, L. salivarius W24, and L. lactis W19. HAMA-14: Hamilton Anxiety Scale. SSRIs: Selective Serotonin Reuptake Inhibitors. SCL-90: Derogatis Symptom Checklist. PSS-10: Perceived Stress Scale. DASS-42: Depression, Anxiety, and Stress Scales. NR: not reported. QIDS-SR16: Quick Inventory of Depressive Symptomatology. SAMe: S-adenosylmethionine. Z-SDS: Zung Self-Rating Depression Scale. Multispecies probiotic: B. subtilis, B. bifidum, B. breve, B. infantis, B. longum, L. acidophilus, L. delbrueckii subsp. bulgaricus, L. casei, L. plantarum, L. rhamnosus, L. helveticus, L. salivarius, L. lactis, and S. thermophilus. RBANS: Repeatable Battery for the Assessment of Neuropsychological Status. MPI: Memory Performance Index. VIM: Visual Memory Test. VBM: Verbal Memory Test. VLMT: Verbal Learning Memory Test. ADAS-Jcog: Alzheimer’s Disease Assessment Scale-Cognitive. MMSE: Mini-Mental State Examination. HAM-A: Hamilton Anxiety Rating Scale. ** S. thermophiles strain CNCM number I-1630, B. animalis subsp. Lacti, Bifidobacterium bifidum, S. thermophiles, L. bulgaricus strain numbers CNCM I-1632 and I-1519, L. lactis subsp. Lactis strain CNCM number I-1631, L. acidophilus, L. plantarum, L. reuteri, each strain at 1.5 × 1010 CFU. PHQ-9: Patient Health Questionnaire-9. BPD: Bipolar Disorder. PANSS: Positive and Negative Syndrome Scale. BAI: Beck Anxiety Inventory. Sanprobi Barrier®: B. bifidum W23, B. lactis W51, B. lactis W52, L. acidophilus W37, L. brevis W63, L. casei W56, L. salivarius W24, L. lactis W19, and L. lactis W58. Bio-Kult®: B. subtilis PXN® 21, B. bifidum PXN® 23, B. breve PXN® 25, B. infantis PXN® 27, B. longum PXN® 30, L. acidophilus PXN® 35, L. delbrueckii ssp.bulgaricus PXN® 39, L. casei PXN® 37, L. plantarum PXN® 47, L. rhamnosus PXN® 54, L. helveticus PXN® 45, L. salivarius PXN® 57, L. lactis ssp.lactis PXN® 63, S. thermophilus PXN® 66. ETB: Emotional Test Battery. LactoCare®: L. acidophilus, B. lactis, B. bifidum, and B. longum (each 2 × 109). ACPT: Auditory Continuous Performance Test. CES-D: Center for Epidemiologic Studies Depression Scale. Familact H®: L. casaei 3 × 108 CFU/g, L. acidophilus 2 × 108 CFU/g, L. bulgaricus 2 × 109 CFU/g, L. rhamnosus 3 × 108 CFU/g, B. breve 2 × 108 CFU/g, B. longum 1 × 109 CFU/g, S. thermophilus 3 × 108 CFU/g, and 100 mg of fructooligosaccharide. BioCeuticals®: B. bifidum, B. animalis subsp. Lactis, B. longum, L. acidophilus, L. helveticus, L. casei, L. plantarum, L. rhamnosus. GAD-7: Generalized Anxiety Disorder Scale. FamiLact®: L. Acidophilus, L. Casei, L. Delbrueckii subsp. L. Bulgaricus, and L. Rhamnosus, B. Longum and B. Breve and S.Salivarius subsp. Thermophil. Probio-Tec® BG-VCap-6.5: L. rhamnosus and B. animalis subsp. Lactis. YMRS: Young Mania Rating Scale.