Probiotics alone or combined with prebiotics may help ease depression
July 6, 2020
Science Daily/BMJ
Probiotics either taken by themselves or when combined with prebiotics, may help to ease depression, suggests a review of the available evidence, published in BMJ Nutrition Prevention & Health.
But as to whether they might help to lessen anxiety isn't yet clear, say the researchers.
Foods that broaden the profile of helpful bacteria in the gut are collectively known as probiotics, while prebiotics are compounds that help these bacteria to flourish.
In the UK in 2016-17, 1.4 million people were referred with mental health issues, over half of them (53%) had anxiety or stress related disorders, while a third (33%) had depression.
A two-way relationship exists between the brain and digestive tract, known as the gut-brain axis. And the possibility that the microbiome -- the range and number of bacteria resident in the gut -- might help treat mental ill health has become a focus of interest in recent years.
To explore this further, the researchers searched for relevant studies published in English between 2003 and 2019, which looked at the potential therapeutic contribution of pre-and probiotics in adults with depression and/or anxiety disorders.
Out of an initial haul of 71 studies, just 7 met all the criteria for inclusion. All 7 investigated at least 1 probiotic strain; 4 looked at the effect of combinations of multiple strains.
In all, 12 probiotic strains featured in the selected studies, primarily Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium bifidium. One study looked at combined pre-probiotic treatment, while one looked at prebiotic therapy by itself.
The studies varied considerably in their design, methods used, and clinical considerations, but all of them concluded that probiotic supplements either alone or in combination with prebiotics may be linked to measurable reductions in depression.
And every study showed a significant fall or improvement in anxiety symptoms and/or clinically relevant changes in biochemical measures of anxiety and/or depression with probiotic or combined pre-probiotic use.
Of the 12 different probiotics investigated, 11 were potentially useful, the findings showed.
The researchers highlight several caveats to their review: none of the included studies lasted very long; and the number of participants in each was small.
This makes it difficult to draw any firm conclusions about the overall effects, whether they are long lasting, and whether there might be any unwanted side effects associated with prolonged use, they say.
Nevertheless on the basis of the preliminary evidence to date, pre- and probiotic therapy warrant further investigation, they suggest.
Probiotics may help reduce the production of inflammatory chemicals, such as cytokines, as is the case in inflammatory bowel disease, suggest the researchers. Or they may help direct the action of tryptophan, a chemical thought to be important in the gut-brain axis in psychiatric disorders.
As anxiety disorders and depression affect people very differently, they require treatment approaches that take account of these complexities, they say. "In this way, with a better understanding of the mechanisms, probiotics may prove to be a useful tool across a wide range of conditions," they write.
People with depression and/or anxiety disorders also often have other underlying conditions, such as impaired insulin production and irritable bowel syndrome, they point out.
"As such, the effect that probiotics have on patients with [common mental disorders] may be twofold: they may directly improve depression in line with the observed findings of this review, and/or they might beneficially impact a patient's experience of their [common mental disorder] by alleviating additional comorbidities," they write.
"Purely from the information gathered for this review, it is valid to suggest that, for patients with clinically recognised depression: isolate, or adjuvant prebiotic therapy is unlikely to affect an individual's experience of their condition in a quantitatively evident way; and that isolate or adjuvant, probiotic/combined prebiotic-probiotic therapy may offer a quantitatively measurable improvement in parameters relating to depression," they conclude.
"However, there are inadequate data to suggest anything meaningful to support or refute the use of either pre/probiotic agents (or a combination of both) in patients with clinically recognised anxiety disorders; this would be a useful area to investigate further."
https://www.sciencedaily.com/releases/2020/07/200706203820.htm
Brain activity can predict success of depression treatment
April 11, 2018
Science Daily/McLean Hospital
Researchers believe they have uncovered a method that could be useful in predicting a depressed patient's treatment prognosis, prior to starting treatment.
McLean Hospital and Harvard Medical School researchers believe they have uncovered a method that could be useful in predicting a depressed patient's treatment prognosis, prior to starting treatment.
In the paper "Pretreatment Rostral Anterior Cingulate Cortex Activity in Relation to Symptom Improvement in Depression: A Randomized Clinical Trial," currently available online and scheduled to appear in the June 2018 edition of JAMA Psychiatry, the investigative team details its work in identifying whether certain markers in the brain could allow clinicians to identify patients with a high or low likelihood of responding to certain treatments for depression.
The study was jointly first-authored by Diego A. Pizzagalli, PhD, and Christian A. Webb, PhD. "Our work shows that we could predict a patient's response to an antidepressant by looking at the activation level of the rostral anterior cingulate cortex (ACC) region of the brain by using a non-invasive monitoring system to test brain activity called an electroencephalogram -- also known as an EEG," said Diego A. Pizzagalli, director of the McLean Imaging Center as well as the hospital's Center For Depression, Anxiety and Stress Research and Laboratory for Translational and Affective Neuroscience. Webb, assistant professor at Harvard Medical School and director of the Treatment and Etiology of Depression in Youth Laboratory, noted that this is the first study to "demonstrate the 'incremental predictive validity' of this neural marker, that is, the fact that activity in this brain region predicts the likelihood of treatment response above and beyond the contribution of a range of low-cost and easily administered clinical and demographic characteristics previously shown to predict treatment outcome."
For this study, the team built upon Pizzagalli's previous work showing that EEG recordings of rostral ACC activity could predict the eventual response. "In that prior study, we saw that the higher the activity before the start of the treatment, the better the clinical response months later," noted Pizzagalli, who is also a professor of psychiatry at Harvard Medical School.
For the new study, more than 300 patients were tested at four sites in the United States -- using sertraline for the treatment group. "We showed that the rostral ACC marker predicted clinical response eight weeks later, even when statistically controlling for demographics and clinical variables previously linked to treatment response," said Pizzagalli. "For those with the marker of good response, a clinician could tell patients that they have a high chance of benefitting from the intervention, and they should stay engaged in treatment," he explained. Conversely, he said, for patients with the marker of low response, "clinicians could decide to start with more aggressive treatment at the outset, such as a combination of pharmacology and psychotherapy, and importantly, monitor these patients more closely."
Soon, Webb, Pizzagalli, and their colleagues plan to deploy these approaches on patients at McLean Hospital to determine whether they can lead to treatment-specific predictions. "Our vision is to determine if an optimal combination of markers -- including brain-based but also clinical and demographic characteristics -- might allow us to predict response to drug A but not drug B or psychotherapy, for example," Webb explained.
Also, if an ACC marker predicts better response, researchers might develop cognitive training that specifically targets this region, which could increase brain activation to accelerate or boost response to more traditional intervention. Pizzagalli and his team hope to engage in further research into this concept by testing patients with major depressive disorder.
https://www.sciencedaily.com/releases/2018/04/180411111103.htm