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Pharmaceutical Interventions in Chronic Fatigue Syndrome: A Literature-based Commentary.
Richman, S, Morris, MC, Broderick, G, Craddock, TJA, Klimas, NG, Fletcher, MA
Clinical therapeutics. 2019;41(5):798-805
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Myalgic encephalomyelitis, also known as Chronic Fatigue Syndrome (ME/ CFS), is a disease characterized by an inability to exert oneself physically, often coupled with a combination of other symptoms, including sleep disorders, severe unpredictable pain, and compromised cognitive abilities. The aim of this review was to delineate a number of the more prominent treatments for ME/CFS into different categories and evaluate the methods and results of corresponding drug trials. Results indicate that: • antiviral drugs appear to show limited efficacy in treating ME/CFS over a broad demographic. • there is a lack of clinical research focusing on the use of specific cyclooxygenase-2 inhibitors [analgesic] to treat ME/CFS. • antidepressants may be of use in delivering improvements in the quality of life of patients with ME/CFS. • recalibration of endocrine-immune regulation may be involved in supporting the persistence of ME/CFS and may be responsible at least in part for its resistance to single agent interventions. Authors conclude that there is a great need for larger, longitudinal studies focused on a more clearly defined subset of ME/CFS as well as a greater consideration of potential synergies between interventions and the suitability of combination therapies.
Abstract
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disorder characterized by prolonged periods of fatigue, chronic pain, depression, and a complex constellation of other symptoms. Currently, ME/CFS has no known cause, nor are the mechanisms of illness well understood. Therefore, with few exceptions, attempts to treat ME/CFS have been directed mainly toward symptom management. These treatments include antivirals, pain relievers, antidepressants, and oncologic agents as well as other single-intervention treatments. Results of these trials have been largely inconclusive and, in some cases, contradictory. Contributing factors include a lack of well-designed and -executed studies and the highly heterogeneous nature of ME/CFS, which has made a single etiology difficult to define. Because the majority of single-intervention treatments have shown little efficacy, it may instead be beneficial to explore broader-acting combination therapies in which a more focused precision-medicine approach is supported by a systems-level analysis of endocrine and immune co-regulation.
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Clinical symptoms and markers of disease mechanisms in adolescent chronic fatigue following Epstein-Barr virus infection: An exploratory cross-sectional study.
Kristiansen, MS, Stabursvik, J, O'Leary, EC, Pedersen, M, Asprusten, TT, Leegaard, T, Osnes, LT, Tjade, T, Skovlund, E, Godang, K, et al
Brain, behavior, and immunity. 2019;80:551-563
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Epstein-Barr virus (EBV) can trigger chronic fatigue (CF) and chronic fatigue syndrome (CFS) in individuals who are predisposed. However, how fatigue develops and how infections may trigger this is not fully understood. This exploratory cross-sectional study of 200 fatigued and non-fatigued adolescents 6 months after EBV aimed to understand symptoms and potential markers for disease. The results showed that all symptoms (not just fatigue) were more pronounced in those individuals suffering from fatigue, despite no increases in viral load. Those with fatigue only had slight changes in immune, nerve and hormonal markers and none correlated with severity of symptoms. It was concluded that there is a discrepancy between symptoms and viral load and alterations to several markers were only marginal. This study could be used by healthcare professionals to understand the possible limitations of using several biomarkers as a diagnostic tool for CF and CFS.
Abstract
INTRODUCTION Acute Epstein-Barr virus (EBV) infection is a trigger of chronic fatigue (CF) and Chronic Fatigue Syndrome (CFS). The aim of this cross-sectional study was to explore clinical symptoms as well as markers of disease mechanisms in fatigued and non-fatigued adolescents 6 months after EBV-infection, and in healthy controls. MATERIALS AND METHODS A total of 200 adolescents (12-20 years old) with acute EBV infection were assessed 6 months after the initial infectious event and divided into fatigued (EBV CF+) and non-fatigued (EBV CF-) cases based on questionnaire score. The EBV CF+ cases were further sub-divided according to case definitions of CFS. In addition, a group of 70 healthy controls with similar distribution of sex and age was included. Symptoms were mapped with a questionnaire. Laboratory assays included EBV PCR and serology; detailed blood leukocyte phenotyping and serum high-sensitive C-reactive protein; and plasma and urine cortisol and catecholamines. Assessment of autonomic activity was performed with continuous, non-invasive monitoring of cardiovascular variables during supine rest, controlled breathing and upright standing. Differences between EBV CF+ and EBV CF- were assessed by simple and multiple linear regression adjusting for sex as well as symptoms of depression and anxiety. A p-value ≤ 0.05 was considered statistically significant. This study is part of the CEBA-project (Chronic fatigue following acute Epstein-Barr virus infection in adolescents). RESULTS The EBV CF+ group had significantly higher scores for all clinical symptoms. All markers of infection and most immune, neuroendocrine and autonomic markers were similar across the EBV CF+ and EBV CF- group. However, the EBV CF+ group had slightly higher serum C-reactive protein (0.48 vs 0.43 mg/L, p = 0.031, high-sensitive assay), total T cell (CD3+) count (median 1573 vs 1481 × 106 cells/L, p = 0.012), plasma norepinephrine (1420 vs 1113 pmol/L, p = 0.01) and plasma epinephrine (363 vs 237 nmol/L, p = 0.032); lower low-frequency:high frequency (LF/HF) ratio of heart rate variability at supine rest (0.63 vs 0.76, p = 0.008); and an attenuated decline in LF/HF ratio during controlled breathing (-0.11 vs -0.25, p = 0.002). Subgrouping according to different CFS diagnostic criteria did not significantly alter the results. Within the EBV CF+ group, there were no strong correlations between clinical symptoms and markers of disease mechanisms. In a multiple regression analysis, serum CRP levels were independently associated with serum cortisol (B = 4.5 × 10-4, p < 0.001), urine norepinephrine (B = 9.6 × 10-2, p = 0.044) and high-frequency power of heart rate variability (B = -3.7 × 10-2, p = 0.024). CONCLUSIONS In adolescents, CF and CFS 6 months after acute EBV infection are associated with high symptom burden, but no signs of increased viral load and only subtle alterations of immune, autonomic, and neuroendocrine markers of which no one is strongly correlated with symptom scores. A slight sympathetic over parasympathetic predominance is evident in CF and might explain slightly increased CRP levels.
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Use of Meditation and Cognitive Behavioral Therapies for the Treatment of Stress, Depression and Anxiety in Students. A Systematic Review and Meta-Analysis.
González-Valero, G, Zurita-Ortega, F, Ubago-Jiménez, JL, Puertas-Molero, P
International journal of environmental research and public health. 2019;16(22)
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Research in the field of the mind is increasing, with students becoming key objects of study in the field of social sciences and health. The main aim of this study was to review the scientific literature in order to analyze the effect produced by cognitive-behavioural programs and meditation strategies on stress, anxiety, and depression in students. A secondary aim was to identify the determinants of treatment success. This study is a systemic review and meta-analysis of 34 articles which included 3296 participating students. A total of 22 effect sizes were calculated for stress treatment, 28 for anxiety and 28 for depression. Results show that interventions based on cognitive-behavioural programs, self-reflection, and mindfulness-based approaches produce satisfactory and significant results in relation to the reduction of stress, anxiety, and depression in students. Furthermore, taking into consideration the theoretical foundations of the studies analysed, meditation (mindfulness, yoga and tai chi), muscle relaxation and breathing, coaching, and cognitive-behavioural therapy are strategies that have shown effectiveness in improving mental health. Authors conclude that it is essential to focus attention on how to improve the mental health of students, including an increase in the number of interventions in the classroom.
Abstract
The prevalence of mental health problems within students due to high academic demands and learning difficulties is a current challenge the field of education. The aim of this study is to review the scientific literature in order to analyze the effect produced by cognitive-behavioral programs and meditation strategies on stress, anxiety, and depression in students. A further aim is to identify the determinants of treatment success. The bibliographic search was carried out using Web of Science, specifically in the categories of "Education and Educational Research" and "Psychology", obtaining a sample of 122 articles published between 2007 and 2018. Studies were included which had a pre-experimental or quasi-experimental design and included pre-test and post-test phases. Following application of inclusion criteria, 34 articles were selected for inclusion in a meta-analysis of the random effects of each variable. This obtained an average effect size of -0.41 for stress, -0.37 for anxiety, and -0.30 for depression. Three moderating variables were analyzed, with significant correlations being found for the type of treatment relating to stress (Q = 11.01, df = 2, p = 0.004, R2 = 0.294) and depression (Q = 6.14, df = 2, p = 0.048; R2 = 0.436). The stage of education of the individuals was also found to impact upon anxiety intervention success (Q = 13.093 df = 2, p = 0.0009, R2 = 0.196). Interventions mainly addressed the importance of meditation strategies, mindfulness programs, and cognitive-behavioral therapy to reduce stress, anxiety, and depression in students. This supports the need to increase research at an early age, considering the treatment of mental health as a key factor influencing academic performance and quality of life.
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Anxiety reduction through art therapy in women. Exploring stress regulation and executive functioning as underlying neurocognitive mechanisms.
Abbing, A, de Sonneville, L, Baars, E, Bourne, D, Swaab, H
PloS one. 2019;14(12):e0225200
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Anxiety treatments currently involve medication and changing an individual’s beliefs through cognitive behavioural therapy (CBT). Art therapy (AT) is often used as a CBT treatment strategy, although little is known about its effectiveness. This randomised control trial of 47 adult women with anxiety aimed to understand the role of AT in anxiety treatment over three months. The results showed improvements in self-reported measures of anxiety, the ability to control emotions, memory and the ability to manage tasks with AT, however subjects were just as susceptible to stress following treatment. It was concluded that anxiety reduction was related to improvements in emotions, memory and task management and this was as a result of AT. This study could be used by healthcare professionals to recommend AT to individuals with symptoms of anxiety as part of their treatment management plan.
Abstract
OBJECTIVES To explore possible working mechanisms of anxiety reduction in women with anxiety disorders, treated with art therapy (AT). METHODS A RCT comparing AT versus waiting list (WL) condition on aspects of self-regulation. Stress regulation (heart rate and heart rate variability) and executive functioning (daily behavioural and cognitive performance aspects of executive functioning (EF)) were evaluated in a pre-post design. Participants were women, aged 18-65 years with moderate to severe anxiety symptoms. RESULTS Effectiveness of AT compared to WL was demonstrated in a higher resting HRV post treatment, improvements in aspects of self-reported daily EF (emotion control, working memory, plan/organize and task monitor), but not in cognitive performance of EF, stress responsiveness and down regulation of stress. The decrease in anxiety level was associated with improvements in self-reported daily EF. CONCLUSIONS AT improves resting HRV and aspects of EF, the latter was associated with art therapy-related anxiety reduction.
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Internet-Delivered Acceptance and Commitment Therapy for Anxiety Treatment: Systematic Review.
Kelson, J, Rollin, A, Ridout, B, Campbell, A
Journal of medical Internet research. 2019;21(1):e12530
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Anxiety and its related conditions are highly prevalent on a global scale. A potential solution for people with anxiety is Acceptance and Commitment Therapy (ACT)—a psychological treatment that teaches mindfulness skills to help people accept their anxiety and commit to living in accordance with personal values. The aim of this study was to provide a comprehensive and up-to-date account on the empirical status of internet-delivered ACT for anxiety. This study is a systemic review of 20 studies. More than half of the studies were randomised control trials. Findings indicate small-to-large anxiety reductions among participants (suffering from generalized anxiety disorder, social anxiety disorder and illness anxiety disorder) after internet-derived ACT on standardized measures (studies n=18), thus indicating the beneficial impact of internet-derived ACT on anxiety. Authors conclude that their current findings indicate that internet-derived ACT can be an effective and acceptable treatment for some anxiety conditions among young to middle aged adults in Western societies.
Abstract
BACKGROUND Anxiety conditions are debilitating and prevalent throughout the world. Acceptance and Commitment Therapy (ACT) is an effective, acceptance-based behavioral therapy for anxiety. However, there are treatment barriers (eg, financial, geographical, and attitudinal), which prevent people from accessing it. To overcome these barriers, internet-delivered ACT (iACT) interventions have been developed in recent years. These interventions use websites to deliver ACT information and skill training exercises on the Web, either as pure self-help or with therapist guidance. OBJECTIVE This systematic review aimed to examine the therapeutic impact of iACT on all anxiety conditions. METHODS The EMBASE, MEDLINE, ProQuest Central, PsycINFO, Scopus, and Web of Science databases were searched up to September 2018. The titles and abstracts of remaining records after deduplication were screened by 2 authors with a total of 36 full-text articles being retained for closer inspection next to eligibility criteria. Empirical studies of all designs, population types, and comparator groups were included if they appraised the impact of iACT treatment on any standardized measure of anxiety. Included studies were appraised on methodological quality and had their data extracted into a standardized coding sheet. Findings were then tabulated, and a narrative synthesis was performed because of the heterogeneity found between studies. RESULTS A total of 20 studies met inclusion criteria. There were 11 randomized controlled trials (RCTs) and 9 uncontrolled pilot studies. Participants across all studies were adults. The anxiety conditions treated were as follows: generalized anxiety disorder (GAD), social anxiety disorder (SAD), illness anxiety disorder (IAD), and general anxiety symptoms, with or without comorbid physical and mental health problems. A total of 18 studies reported significant anxiety reduction after iACT treatment. This was observed in studies that delivered iACT with (n=13) or without (n=5) therapist guidance. The average attrition rate across all included studies during the active iACT treatment phase was 19.19%. In the 13 studies that assessed treatment satisfaction, participants on average rated their iACT experience with above average to high treatment satisfaction. CONCLUSIONS These findings indicate that iACT can be an efficacious and acceptable treatment for adults with GAD and general anxiety symptoms. More RCT studies are needed to corroborate these early iACT findings using empirical treatments in active control groups (eg, internet-delivered cognitive behavioral therapy). This would potentially validate the promising results found for SAD and IAD as well as address the full spectrum of anxiety disorders.
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Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial.
Hidese, S, Ogawa, S, Ota, M, Ishida, I, Yasukawa, Z, Ozeki, M, Kunugi, H
Nutrients. 2019;11(10)
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L-theanine (γ-glutamylethylamide) is a unique non-protein amino acid found in green tea (Camellia sinensis), a widely consumed beverage associated with human health. The aim of this study was to examine the effects of four weeks L-theanine administration (200 mg/day, four weeks) in a healthy population, i.e., individuals without any major psychiatric disorder. This study is a randomized, placebo-controlled, crossover, and double-blind trial. The study enrolled thirty individuals (n = 9 men and n = 21 women). Participants received either an enzymatic synthetic product L-theanine or placebo tablets who had to orally self-administer before sleep each night for four weeks. Results show that four weeks L-theanine administration has positive effects on stress-related symptoms and cognitive function in a healthy population. Furthermore, the reduction in sleep quality problems (disturbances in sleep latency, sleep disturbance and use of sleep medication) was greater in the L-theanine administration compared to the placebo administration, while verbal fluency, especially letter fluency, was improved in the L-theanine administration among individuals who showed relatively low performance at pre-treatment. Authors conclude that L-theanine may be a suitable nutraceutical ingredient for improving mental conditions in a healthy population.
Abstract
This randomized, placebo-controlled, crossover, and double-blind trial aimed to examine the possible effects of four weeks L-theanine administration on stress-related symptoms and cognitive functions in healthy adults. Participants were 30 individuals (nine men and 21 women; age: 48.3 ± 11.9 years) who had no major psychiatric illness. L-theanine (200 mg/day) or placebo tablets were randomly and blindly assigned for four-week administration. For stress-related symptoms, Self-rating Depression Scale, State-Trait Anxiety Inventory-trait, and Pittsburgh Sleep Quality Index (PSQI) scores decreased after L-theanine administration (p = 0.019, 0.006, and 0.013, respectively). The PSQI subscale scores for sleep latency, sleep disturbance, and use of sleep medication reduced after L-theanine administration, compared to the placebo administration (all p < 0.05). For cognitive functions, verbal fluency and executive function scores improved after L-theanine administration (p = 0.001 and 0.031, respectively). Stratified analyses revealed that scores for verbal fluency (p = 0.002), especially letter fluency (p = 0.002), increased after L-theanine administration, compared to the placebo administration, in individuals who were sub-grouped into the lower half by the median split based on the mean pretreatment scores. Our findings suggest that L-theanine has the potential to promote mental health in the general population with stress-related ailments and cognitive impairments.
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Gut feelings: A randomised, triple-blind, placebo-controlled trial of probiotics for depressive symptoms.
Chahwan, B, Kwan, S, Isik, A, van Hemert, S, Burke, C, Roberts, L
Journal of affective disorders. 2019;253:317-326
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Depression is a debilitating psychiatric disorder that is the leading cause of disability world-wide. Multiple causes of depression have been identified, including genetic, neurological, inflammatory, personality, cognitive, and environmental factors. The aim of this study was to investigate the effectiveness of the multispecies probiotic Ecologic® Barrier for reducing symptoms in adults with mild to severe levels of depression. The study was a triple-blinded parallel, placebo-controlled randomised clinical trial. Participants were randomly allocated into two groups; probiotic and placebo. 71 participants with depressive symptoms were recruited and allocated sequentially over 12 months. Results indicate that all participants across both probiotic and placebo groups exhibited a reduction in depressive symptoms over the time-period of the trial. Thus, the routine involved with daily preparation and consumption of the probiotic and scheduled appointments, as well as involvement in these behaviours with the aim of seeking improvement in depressive symptoms had positive impacts on mood, irrespective of whether the probiotic or placebo was consumed. Authors conclude that their findings offer evidence to indicate that probiotic consumption can exert change on cognitive patterns associated with depression.
Expert Review
Conflicts of interest:
None
Take Home Message:
- This study offers evidence to indicate that probiotic consumption can exert change on cognitive patterns associated with depression.
- The study suggests that probiotics, rather than having a direct effect on depressive symptoms, potentially act on immune system activity, inflammation and gut barrier integrity which contribute to the expression of depression.
- Probiotics may be a useful adjunct to potentiate the effects of other therapies, such as CBT.
- This study points to the validity of managing physical health as part of mental health treatment.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
With evidence suggesting that decreased gut barrier function and inflammation are correlated with depression, this study set out to determine the effect of consumption of probiotic supplements on depressive symptoms from a sample of 71 participants with depression. The study was a triple-blinded parallel, placebo-controlled randomised clinical trial conducted over 8 weeks in Australia. Pre and post intervention measures of symptoms and vulnerability markers of depression as well as gut microbiota were compared alongside psychological variables and gut microbiota composition to non-depressed, placebo and probiotic groups. All the clinical trial participants demonstrated an improvement in symptoms – participants in the probiotic group demonstrated a significantly greater reduction in cognitive reactivity compared with the placebo group. Probiotics did not significantly alter the microbiota of depressed individuals, however a significant correlation was found between Ruminococcus gnavus and one of the metrics for depression.
Clinical practice applications:
This study was small and carried out over a short period of time. While significant results were found, which signify potential considerations for clinical practice, the results from this study do not offer evidence that the probiotics used had a direct effect on depressive symptoms – they suggest that probiotics potentially act on cognitive processes contributing to depression which may include immune system activity, inflammation, and gut barrier integrity. Overall, this study offers evidence to indicate that probiotic consumption can exert change on cognitive patterns associated with depression. In clinical practice, probiotics may be a useful adjunct to potentiate the effects of therapies, such as CBT. Finally, the use of probiotics promotes the concept of managing physical health as part of mental health treatment.
Considerations for future research:
These preliminary results are promising and offer a number of future research and clinical avenues to build upon. The results do however, indicate that a longer trial may be needed to fully assess the effects of probiotics on mood and the mechanisms by which probiotics may be influencing this. The study also suggests that further research using a range of concentrations in a dose response study may be warranted to determine the optimal dose; a greater dose over a longer period may produce detectable changes in microbiota as well as further differences in psychological data.
Abstract
BACKGROUND Depression is the leading cause of disability worldwide; with evidence suggesting that decreased gut barrier function and inflammation are correlated with depressive symptoms. We conducted a clinical trial to determine the effect of consumption of probiotic supplements (Winclove's Ecologic® Barrier) on depressive symptoms in a sample of participants with mild to severe depression. METHOD 71 participants were randomly allocated to either probiotic or placebo, which was, consumed daily over eight weeks. Pre- and post-intervention measures of symptoms and vulnerability markers of depression as well as gut microbiota composition were compared. Clinical trial participants were also compared on psychological variables and gut microbiota composition to a non-depressed group (n = 20). RESULTS All clinical trial participants demonstrated improvement in symptoms, suggesting non-specific therapeutic effects associated with weekly monitoring visits. Participants in the probiotic group demonstrated a significantly greater reduction in cognitive reactivity compared with the placebo group, particularly in the mild/moderate subgroup. Probiotics did not significantly alter the microbiota of depressed individuals, however, a significant correlation was found between Ruminococcus gnavus and one depression metric. LIMITATIONS There was a high attrition rate, which may be attributed to weekly monitoring visits. Additionally, modulation of the gut microbiota may need more specific testing to distinguish subtle changes. CONCLUSIONS While microbiota composition was similar between all groups, probiotics did affect a psychological variable associated with susceptibility to depression. Further research is needed to investigate how probiotics can be utilised to modify mental wellbeing, and whether they can act as an adjunct to existing treatments.
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The Gut Microbiome and Mental Health: What Should We Tell Our Patients?: Le microbiote Intestinal et la Santé Mentale : que Devrions-Nous dire à nos Patients?
Butler, MI, Mörkl, S, Sandhu, KV, Cryan, JF, Dinan, TG
Canadian journal of psychiatry. Revue canadienne de psychiatrie. 2019;64(11):747-760
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The gut-brain axis is the bi-directional communication pathway and increasing evidence indicates its impact in neural health and disease. With the field of nutritional psychiatry actively developing, psychiatric patients have become increasingly aware of the therapeutic use of probiotics and mental health. This review aims to inform psychiatrists about the communication between the microbiome and brain and discuss its relevance to the management and treatment of psychiatric illness. In reviewing the common psychiatric illnesses, the current literature shows inconsistent results on specific microbiome compositions related to specific illnesses, yet shows promising effects for probiotic use in many disorders. These findings offer a novel paradigm for approaching mental illness through the lens of nutritional psychiatry. Authors conclude there is much work to be done translating laboratory findings into clinical practice, and highlight the necessity for clinicians to stay informed of the literature and make accurate recommendations to patients.
Abstract
The gut microbiome as a potential therapeutic target for mental illness is a hot topic in psychiatry. Trillions of bacteria reside in the human gut and have been shown to play a crucial role in gut-brain communication through an influence on neural, immune, and endocrine pathways. Patients with various psychiatric disorders including depression, bipolar disorder, schizophrenia, and autism spectrum disorder have been shown to have significant differences in the composition of their gut microbiome. Enhancing beneficial bacteria in the gut, for example, through the use of probiotics, prebiotics, or dietary change, has the potential to improve mood and reduce anxiety in both healthy people and patient groups. Much attention is being given to this subject in the general media, and patients are becoming increasingly interested in the potential to treat mental illness with microbiome-based therapies. It is imperative that those working with people with mental illness are aware of the rationale and current evidence base for such treatment strategies. In this review, we provide an overview of the gut microbiome, what it is, and what it does in relation to gut-brain communication and psychological function. We describe the fundamental principles and basic techniques used in microbiome-gut-brain axis research in an accessible way for a clinician audience. We summarize the current evidence in relation to microbiome-based strategies for various psychiatric disorders and provide some practical advice that can be given to patients seeking to try a probiotic for mental health benefit.
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Gut feeling: randomized controlled trials of probiotics for the treatment of clinical depression: Systematic review and meta-analysis.
Nikolova, V, Zaidi, SY, Young, AH, Cleare, AJ, Stone, JM
Therapeutic advances in psychopharmacology. 2019;9:2045125319859963
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Major depression is a common and complex illness that significantly diminishes quality of life. Currently, most pharmacological treatments target neurotransmitter activity in the brain and are known to have a delayed onset of effect as well as a range of side-effects. The aim of this study was to identify and synthesize all published data from randomized controlled trials (RCTs) on the efficacy of probiotics as treatment for depression in clinically depressed patients. This study is a systematic review of three studies. Within the three included RCTs, a total of 229 clinically depressed patients were randomized, with an average age of 36 years and a gender distribution of 76% female. Results indicate a non-significant difference in depressive symptoms between the probiotic and placebo groups post-intervention. Authors conclude that further larger studies in well-defined clinical populations are needed, both to determine the clinical utility of this novel treatment approach, and to investigate potential underlying mechanisms.
Abstract
BACKGROUND Recently the gut microbiota has attracted significant interest in psychiatric research due to the observed bidirectional gut-brain communication. A growing body of evidence from preclinical work has suggested that probiotics may be effective in reducing stress and anxiety and alleviating low mood. It is unclear to what extent these effects are seen in clinical populations. We aimed to identify all published evidence on the efficacy of probiotics as treatment for depression in clinically depressed populations. METHODS Randomized controlled trials of patients with depression where probiotics were used as supplementary or standalone treatment were considered eligible. A literature search with the terms (probiotic* OR bacteria OR Lactobacillus OR Bifidobacterium) AND depress* was performed in PubMed and Web of Science. Data on study population characteristics, treatment effectiveness, tolerability and risk of bias were extracted from eligible studies. A random effects model was used for meta-analyses. RESULTS Only three studies met inclusion criteria (229 individuals randomized), two of which administered probiotics as a supplementary treatment to antidepressants and one as a standalone treatment. Upon removal of the latter study from the meta-analysis due to clinical heterogeneity, there was an overall positive effect of probiotics on depressive symptoms (standardized mean difference = 1.371, 95% confidence interval 0.130-2.613). CONCLUSIONS There is limited evidence for the efficacy of probiotics in depression at present, although there may be a beneficial effect of probiotics on depressive symptoms when administered in addition to antidepressants. Further studies are required to investigate this and explore potential mechanisms.
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Systematic Review of Gut Microbiota and Major Depression.
Cheung, SG, Goldenthal, AR, Uhlemann, AC, Mann, JJ, Miller, JM, Sublette, ME
Frontiers in psychiatry. 2019;10:34
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A growing body of research points to a possible association between the gut microbiome and major depressive disorder (MDD). The gut microbiome is a collection of trillions of microorganisms, including different taxonomic groups of bacteria. The aim of this review is to assess the literature to identify the relationship between the gut microbiome composition and MDD and to highlight potential metabolic mechanisms contributing to the development of MDD. Six eligible studies demonstrated significant differences in gut microbiome composition between MDD and control groups. While the composition differed between the two groups, there was no consensus on which specific bacteria taxa are most relevant to MDD. Based on these results, the authors conclude the data is very limited and the impact of microbiome differences related to depression is currently unclear. They propose future studies should look beyond taxonomic classification and investigate microbial functioning to provide a larger-scale understanding of how the gut microbiome contributes to the development of MDD.
Abstract
Background: Recently discovered relationships between the gastrointestinal microbiome and the brain have implications for psychiatric disorders, including major depressive disorder (MDD). Bacterial transplantation from MDD patients to rodents produces depression-like behaviors. In humans, case-control studies have examined the gut microbiome in healthy and affected individuals. We systematically reviewed existing studies comparing gut microbial composition in MDD and healthy volunteers. Methods: A PubMed literature search combined the terms "depression," "depressive disorder," "stool," "fecal," "gut," and "microbiome" to identify human case-control studies that investigated relationships between MDD and microbiota quantified from stool. We evaluated the resulting studies, focusing on bacterial taxa that were different between MDD and healthy controls. Results: Six eligible studies were found in which 50 taxa exhibited differences (p < 0.05) between patients with MDD and controls. Patient characteristics and methodologies varied widely between studies. Five phyla-Bacteroidetes, Firmicutes, Actinobacteria, Fusobacteria, and Protobacteria-were represented; however, divergent results occurred across studies for all phyla. The largest number of differentiating taxa were within phylum Firmicutes, in which nine families and 12 genera differentiated the diagnostic groups. The majority of these families and genera were found to be statistically different between the two groups in two identified studies. Family Lachnospiraceae differentiated the diagnostic groups in four studies (with an even split in directionality). Across all five phyla, nine genera were higher in MDD (Anaerostipes, Blautia, Clostridium, Klebsiella, Lachnospiraceae incertae sedis, Parabacteroides, Parasutterella, Phascolarctobacterium, and Streptococcus), six were lower (Bifidobacterium, Dialister, Escherichia/Shigella, Faecalibacterium, and Ruminococcus), and six were divergent (Alistipes, Bacteroides, Megamonas, Oscillibacter, Prevotella, and Roseburia). We highlight mechanisms and products of bacterial metabolism as they may relate to the etiology of depression. Conclusions: No consensus has emerged from existing human studies of depression and gut microbiome concerning which bacterial taxa are most relevant to depression. This may in part be due to differences in study design. Given that bacterial functions are conserved across taxonomic groups, we propose that studying microbial functioning may be more productive than a purely taxonomic approach to understanding the gut microbiome in depression.