Table 1 Characteristics of included studies
From: The effects of probiotics on depressive symptoms in humans: a systematic review
Reference | Sample characteristics | Strain | Study design | Duration of intervention | Measurement | Key findings and conclusions |
|---|---|---|---|---|---|---|
Akkasheh et al. [46] | 40 MDD patients. Ages 20–55 years | Lactobacillus acidophilus, L. casei, and Bifidobacterium bifidum | Double-blind, randomized, placebo-controlled trial | 8 weeks | BDI | Consumption of probiotic supplement improved BDI scores |
Benton et al. [42] | 124 healthy humans. Avg. age 62 years | L. casei | Double-blind, randomized, placebo-controlled trial | 3 weeks | POMS, self-rated mood | No effect of probiotic on POMS results. Consumption of probiotic-containing yogurt improved self-reported mood of those whose mood was initially poor |
Chung et al. [44] | 36 healthy humans. Age 60–75 years | L. helveticus | Double-blind, randomized, placebo-controlled trial | 12 weeks | PSS, GDS-SF, DST, SRT, VLT, RVIP, Stroop Task | No significant effects of probiotics on the PSS, GDS-SF. Consumption of probiotics did improve DST, SRT, VLT, RVIP, and stroop tasks scores. |
Gruenwald et al. [48] | 34 adults suffering from stress or exhaustion. Mean age 44 years | L. acidophilus and B. bifidum and longum | Pre- and post-intervention assessment | 6 months | PNQ, EWL | Subjects’ general condition improved by 40.7%. 73% of participants rated the effect of treatment as “good” or “very good” |
Hilimire et al. [50] | 710 young adults. Mean age 19 years | Unknown | Self-report questionnaires on fermented food consumption, neuroticism and social anxiety | N/A | BFI, SPAI-23 | Consumption of fermented foods containing probiotics was negatively associated with symptoms of social anxiety and interacts with neuroticism to predict social anxiety symptoms. Those at higher genetic risk for social anxiety disorder (indexed by high neuroticism) show fewer social anxiety symptoms when they consume more fermented foods. |
Marcos et al. [49] | 136 healthy students. Age 18–23 years | L. casei | Prospective, randomized, controlled, parallel study | 6 weeks | STAI | No significant effects of probiotics on anxiety levels. Probiotics did modulate lymphocyte and CD56 cell counts |
Messaoudi et al. [36] | 55 healthy Caucasians. Mean age 43 years | L. helveticus and B. longum | Double-blind, randomized, controlled, parallel study | 30 days | HADS, HSCL-90, PSS, CCL | Consumption of probiotics reduced global severity index of the HSCL-90 due to lower somatization, depression, and anger-hostility and also reduced HADS global scores. Consumption of probiotic reduced self-blame score on CCL and increased focus on problem solving. No effect on PSS |
Messaoudi et al. [47] | Sub-population of above sample of 25 with lowest UFC levels | L. helveticus and B. longum | Double-blind, randomized, controlled, parallel study | 30 days | HADS, HSCL-90 | Consumption of probiotics reduced HADS and HSCL-90 scores |
Rao et al. [43] | 35 CFS patients. Age 18–65 years | L. casei | Double-blind, randomized, placebo-controlled pilot study | 2 months | BDI, BAI | Consumption of probiotics significantly improved BAI scores. No effect on BDI scores |
Steenbergen et al. [45] | 40 non-smoking healthy young adults. Mean age 20 years | B. lactis and L. acidophilus, brevis, casei, lactis, and salivarius | Triple-blind, randomized, placebo-controlled, pre- and post-intervention assessment | 4 weeks | LEIDS-r | Consumption of multispecies probiotic significantly reduced overall cognitive reactivity to depression (in particular aggressive and ruminative thoughts) |