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Multispecies probiotic administration reduces emotional salience and improves mood in subjects with moderate depression: a randomised, double-blind, placebo-controlled study.
Baião, R, Capitão, LP, Higgins, C, Browning, M, Harmer, CJ, Burnet, PWJ
Psychological medicine. 2023;53(8):3437-3447
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Plain language summary
Gut microbiota may be able to augment an individual’s mood, brain processing and cognition. Supplements containing live bacteria or a diet high in fibre which act as a substrate for beneficial gut bacteria may be of benefit to individuals with depression or mental illness. This 4-week randomised control trial aimed to determine the effect of a probiotic containing several different gut bacteria species on emotional processing and cognition in people with mild to moderate depression. The results showed that compared to placebo, probiotic intake increased empathy with others and improved some but not all aspects of cognition. Probiotic intake did not affect biological measures of stress but did improve feelings of depression. It was concluded that multispecies probiotics may change the emotional processing of people with depression. This study could be used by healthcare professionals to understand that the use of probiotics may be a good option to reduce the risk of people with mild to moderate depression developing a major depressive disorder.
Abstract
BACKGROUND The potential antidepressant properties of probiotics have been suggested, but their influence on the emotional processes that may underlie this effect is unclear. METHODS Depressed volunteers (n = 71) were recruited into a randomised double-blind, placebo-controlled study to explore the effects of a daily, 4-week intake of a multispecies probiotic or placebo on emotional processing and cognition. Mood, anxiety, positive and negative affect, sleep, salivary cortisol and serum C-reactive peptide (CRP) were assessed before and after supplementation. RESULTS Compared with placebo, probiotic intake increased accuracy at identifying faces expressing all emotions (+12%, p < 0.05, total n = 51) and vigilance to neutral faces (mean difference between groups = 12.28 ms ± 6.1, p < 0.05, total n = 51). Probiotic supplementation also reduced reward learning (-9%, p < 0.05, total n = 51), and interference word recall on the auditory verbal learning task (-18%, p < 0.05, total n = 50), but did not affect other aspects of cognitive performance. Although actigraphy revealed a significant group × night-time activity interaction, follow up analysis was not significant (p = 0.094). Supplementation did not alter salivary cortisol or circulating CRP concentrations. Probiotic intake significantly reduced (-50% from baseline, p < 0.05, n = 35) depression scores on the Patient Health Questionnaire-9, but these did not correlate with the changes in emotional processing. CONCLUSIONS The impartiality to positive and negative emotional stimuli or reward after probiotic supplementation have not been observed with conventional antidepressant therapies. Further studies are required to elucidate the significance of these changes with regard to the mood-improving action of the current probiotic.
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Acceptability, Tolerability, and Estimates of Putative Treatment Effects of Probiotics as Adjunctive Treatment in Patients With Depression: A Randomized Clinical Trial.
Nikolova, VL, Cleare, AJ, Young, AH, Stone, JM
JAMA psychiatry. 2023;80(8):842-847
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About 60% of patients with major depressive disorder (MDD) do not fully respond to anti-depressant treatments. The microbiota-gut-brain axis is thought to be involved in the development of MDD, making the microbiome a promising target for new treatments. The aim of this double-blind, randomised, placebo-controlled trial, including 50 adult patients with major depressive disorder, was to evaluate the tolerability, acceptability and efficacy of a multi-strain probiotic supplement for 8 weeks as an adjunctive to antidepressant drugs. There were no serious adverse events; all reported non-serious events were of gastrointestinal nature and more common in the probiotic group (it was not reported whether the difference was statistically significant). A high adherence rate of 97.2% suggests a high level of acceptability. Depressive mood symptoms improved significantly more in the probiotic group. Greater improvements in anxiety in the probiotic were also seen in some, but not all anxiety scales. The authors concluded that a multi-strain probiotic supplement is a promising adjunct to anti-depressant treatment in patients with MDD, with high tolerability and acceptability.
Abstract
IMPORTANCE The microbiota-gut-brain axis is a promising target for novel treatments for mood disorders, such as probiotics. However, few clinical trials have been conducted, and further safety and efficacy data are needed to support this treatment approach. OBJECTIVE To provide acceptability and tolerability data and estimates of intervention effect size for probiotics as adjunctive treatment for patients with major depressive disorder (MDD). DESIGN, SETTING, AND PARTICIPANTS In this single-center, double-blind, placebo-controlled pilot randomized clinical trial, adults aged 18 to 55 years with MDD taking antidepressant medication but having an incomplete response were studied. A random sample was recruited from primary and secondary care services and general advertising in London, United Kingdom. Data were collected between September 2019 and May 2022 and analyzed between July and September 2022. INTERVENTION Multistrain probiotic (8 billion colony-forming units per day) or placebo daily for 8 weeks added to ongoing antidepressant medication. MAIN OUTCOMES AND MEASURES The pilot outcomes of the trial were retention, acceptability, tolerability, and estimates of putative treatment effect on clinical symptoms (depression: Hamilton Depression Rating Scale [HAMD-17] and Inventory of Depressive Symptomatology [IDS] scores; anxiety: Hamilton Anxiety Rating Scale [HAMA] and General Anxiety Disorder [GAD-7] scores) to be used as indicators for a definitive trial. RESULTS Of 50 included participants, 49 received the intervention and were included in intent-to-treat analyses; of these, 39 (80%) were female, and the mean (SD) age was 31.7 (9.8) years. A total of 24 were randomized to probiotic and 25 to placebo. Attrition was 8% (1 in the probiotic group and 3 in the placebo group), adherence was 97.2%, and there were no serious adverse reactions. For the probiotic group, mean (SD) HAMD-17 scores at weeks 4 and 8 were 11.00 (5.13) and 8.83 (4.28), respectively; IDS, 30.17 (11.98) and 25.04 (11.68); HAMA, 11.71 (5.86) and 8.17 (4.68); and GAD-7, 7.78 (4.12) and 7.63 (4.77). For the placebo group, mean (SD) HAMD-17 scores at weeks 4 and 8 were 14.04 (3.70) and 11.09 (3.22), respectively; IDS, 33.82 (9.26) and 29.64 (9.31); HAMA, 14.70 (5.47) and 10.95 (4.48); and GAD-7, 10.91 (5.32) and 9.48 (5.18). Standardized effect sizes (SES) from linear mixed models demonstrated that the probiotic group attained greater improvements in depressive symptoms according to HAMD-17 scores (week 4: SES, 0.70; 95% CI, 0.01-0.98) and IDS Self Report scores (week 8: SES, 0.64; 95% CI, 0.03-0.87) as well as greater improvements in anxiety symptoms according to HAMA scores (week 4: SES, 0.67; 95% CI, 0-0.95; week 8: SES, 0.79; 95% CI, 0.06-1.05), but not GAD-7 scores (week 4: SES, 0.57; 95% CI, -0.01 to 0.82; week 8: SES, 0.32; 95% CI, -0.19 to 0.65), compared with the placebo group. CONCLUSIONS AND RELEVANCE The acceptability, tolerability, and estimated effect sizes on key clinical outcomes are promising and encourage further investigation of probiotics as add-on treatment for people with MDD in a definitive efficacy trial. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT03893162.