The Gut-Brain-Axis is a bidirectional signaling pathway between the gastrointestinal (GI) tract and the brain. The hundreds of trillions of microorganisms populating the gastrointestinal tract are ...thought to modulate this connection, and have far reaching effects on the immune system, central and autonomic nervous systems, and GI functioning. These interactions Diagnostic and statistical manual of mental disorders have also been linked to various psychiatric illnesses such as depression, anxiety, substance abuse, autism spectrum disorder, and eating disorders. It is hypothesized that techniques aimed at strengthening and repopulating the gut microbiome, such as Fecal Microbiota Transplant (FMT), may be useful in the prevention and treatment of psychiatric illnesses.
A systematic search of five databases was conducted using key terms related to FMT and psychiatric illnesses. All results were then evaluated based on specific eligibility criteria.
Twenty-one studies met the eligibility criteria and were analysed for reported changes in mood and behavioural measures indicative of psychiatric wellbeing. The studies included were either entirely clinical (n = 8), preclinical with human donors (n = 9), or entirely preclinical (n = 11). All studies found a decrease in depressive and anxiety-like symptoms and behaviours resulting from the transplantation of healthy microbiota. The inverse was also found, with the transmission of depressive and anxiety-like symptoms and behaviours resulting from the transplantation of microbiota from psychiatrically ill donors to healthy recipients.
There appears to be strong evidence for the treatment and transmission of psychiatric illnesses through FMT. Further research with larger sample sizes and stronger scientific design is warranted in order to fully determine the efficacy and safety of this potential treatment. Registered on PROSPERO, IRD: CRD42019126795.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Many psychiatric illnesses have been linked to the gut microbiome, with supplements such as probiotics showing some efficacy in alleviating the symptoms of some psychiatric illnesses. The aim of this ...review is to evaluate the current literature investigating the effects of adjuvant probiotic or synbiotic administration in combination with first-line treatments for psychiatric illnesses.
A systematic search of four databases was conducted using key terms related to treatments for psychiatric illnesses, the gut microbiome, and probiotics. All results were then evaluated based on specific eligibility criteria.
Eight studies met eligibility criteria and were analyzed for reported changes in outcome measures used to assess the symptoms of psychiatric illness and the tolerability of treatment. All Major Depressive Disorder (MDD) (
= 5) and Generalized Anxiety Disorder (GAD) (
= 1) studies found adjuvant probiotic or synbiotic treatment to be more efficacious in improving the symptoms of psychiatric illness than the first-line treatment alone or with placebo. The schizophrenia studies (
= 2) found adjuvant probiotic treatment to have no significant difference in clinical outcomes, but it was found to improve the tolerability of first-line antipsychotics.
The findings of the studies included in this review suggest the use of adjuvant probiotic treatment with selective serotonin reuptake inhibitors (SSRIs) for MDD and GAD to be superior to SSRI treatment alone. Probiotic adjuvant treatment with antipsychotics could be beneficial for improving the tolerability of the antipsychotics, but these findings do not suggest that adjuvant probiotic treatment would result in improved clinical outcomes for symptoms of schizophrenia.
Recent studies have investigated the potential of treatments that modify the gut microbiome, such as fecal microbiota transplantation and probiotics, in individuals with psychiatric illnesses.
The ...aim of this study was to investigate the safety, tolerability, and efficacy of a novel gut microbiome therapeutic, Microbial Ecosystem Therapuetic-2 (MET-2), in people with depression and anxiety.
In this phase 1, open-label trial, 12 adults diagnosed with major depressive disorder, generalized anxiety disorder, or both were recruited. Over 8 weeks, participants consumed three capsules per day, orally, of an encapsulated microbial therapeutic (MET-2), which contained 40 strains of bacteria that were purified and lab-grown from the stool of a single healthy donor. Participants were assessed biweekly using clinical scales and questionnaires in order to evaluate the safety, efficacy, and tolerability of the therapeutic.
The therapeutic was found to be generally safe and tolerable, with limited adverse events and side effects and no serious adverse events. Of the 12 individuals included in this study, 9 (75%) responded to treatment (50% improvement in Montgomery-Asberg Depression Rating Scale MADRS scores, 7-item Generalized Anxiety Disorder scale GAD-7 scores, or both, from baseline to the week-8 visit). Over the course of 10 weeks, MET-2 significantly decreased mean MADRS and GAD-7 scores (MADRS: F
=8.784, P<.001; GAD-7: F
= 9.638, P<.001). Multiple comparisons with Bonferroni adjustments showed a significant reduction in MADRS scores from baseline (mean 19.00, SD 4.843) to week 6 (mean 11.25, SD 8.001; P=.009), week 8 (mean 8.667, SD 8.732; P=.002), and week 10 (mean 8.250, SD 9.304; P=.006). Multiple comparisons showed a significant reduction in GAD-7 scores from baseline (mean 13.58, SD 4.010) to week 4 (mean 9.167, SD 5.096; P=.03), week 6 (mean 7.667, SD 4.539; P=.004), week 8 (mean 7.333, SD 6.583; P=.03), and week 10 (mean 7.500, SD 6.448; P=.03).
The findings from this study are the first to provide evidence for the role of microbial ecosystem therapy in treating depression and anxiety. However, a double-blind, randomized controlled trial with a larger sample size is needed for more conclusive results.
ClinicalTrials.gov NCT04052451; https://www.clinicaltrials.gov/ct2/show/NCT04052451.
RR2-10.2196/17223.
•Robust evidence suggests that depression, and risk for depression, are associated with the generation of stressful life events.•This systematic review aimed to identify specific molecular genetic ...markers associated with the generation of stressful life events.•There is evidence that genetic variation in the serotonin, HPA axis, and oxytocin systems moderates the effects of psychosocial vulnerability markers on the generation of proximal, dependent life events.•Future research should examine additional genetic markers in systems known to confer risk for stress generation.
Robust evidence suggests that depression, and risk for depression, are associated with the generation of stressful life events. This tendency to generate stress may be genetically determined. This systematic review aimed to identify specific molecular genetic markers associated with the generation of interpersonal stressful life events, at least in part dependent on individuals’ behavior.
We followed the PRISMA guidelines in searching six electronic databases (PubMed, MEDLINE, PsycINFO, CINAHL, Cochrane, and EMBASE) from inception to January 2021, and we reviewed the reference lists of eligible articles for additional records. We restricted eligibility to empirical studies involving at least one genetic marker and including proximal life events. We evaluated the risk of bias using the Newcastle Ottawa Scale for observational studies. The outcome permitted a distinction between life events dependent on the individual's agency versus independent events.
Seven studies, including 3585 participants, met eligibility criteria. Three were longitudinal, and four were cross-sectional; six included adolescents and young adults, and one focused on middle adulthood. Four examined the serotonin-transporter-linked promoter region (5-HTTLPR), two examined the rs53576 single nucleotide polymorphism of the oxytocin receptor gene (OXTR), and one examined a multilocus genetic profile score including four hypothalamic-pituitary-adrenal (HPA) axis genes. There were no significant direct correlations between genotype and life events in any study. Instead, their relation was significantly moderated by symptoms, exposure to early adversity, or attachment. Consistent with the stress generation hypothesis, this moderation relation was significant in predicting exposure to dependent life events but was not significant in predicting independent life event exposure.
There is evidence that genetic variation in the serotonin, HPA axis, and oxytocin systems moderates the effects of psychosocial vulnerability markers on the generation of proximal, dependent life events. Future research should examine additional genetic markers in systems known to confer risk for stress generation.
CRD42019136886.
Transcranial Direct Current Stimulation (tDCS) has been used to modulate empathy, but no studies have meta-analyzed the evidence base for its efficacy. This study aimed to determine the efficacy of ...tDCS at modulating empathy. We conducted a systematic review and meta-analysis of randomized controlled trials involving anodal or cathodal versus sham tDCS to modulate empathy in healthy adults and clinical populations. Random-effects modelling was applied to pooling overall efficacy estimates using standardized mean differences (Hedge's g) and 95% confidence intervals. Outcome measures for tasks designed to measure empathy were reaction time and accuracy. Anodal tDCS appears to improve lab-based computerized measures of cognitive empathy in healthy adult volunteers. While the evidence provided by this review may be of relevance to individuals with impaired empathic capabilities, the generalizability of our findings is geared towards nonclinical populations given the preponderance of healthy volunteers in our review. Hence, it is not clear if moderate improvements in speed and accuracy on lab-based computerized empathy measures would lead to meaningful clinical improvements. Future studies should consider the use of tDCS to modulate empathy in clinical populations.
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