Executive Function (Cognition), Mild-to-moderate Depression, Neural Activity
Conditions
Keywords
Mild-to-moderate Depression, Probiotic Supplementation, Neural Activation, Executive Function
Brief summary
This study aims to investigate the acute and chronic effects of 16-week probiotic supplementation (Ecologic® Barrier) on depressive symptoms and neural activity in those with mild-to-moderate depression.
Detailed description
This study will use a randomised, double-blind, placebo-controlled design. A total of 76 participants will be recruited and will receive either one sachet of the probiotic (Ecologic® Barrier) or one sachet of a placebo, matched in taste, smell, appearance, and packaging. Outcomes will be measured at baseline, 24 hours, and at 16 weeks for all participants. These include measures of general mood, depressive symptoms, executive function, and neural activity. Neural activation will be measured using electroencephalography (EEG), specifically measuring the P300 event-related potential (ERP) during an n-back task. In addition to the n-back task, executive function, specifically working memory and cognitive flexibility will be tested using the task-switching task. The main question this study aims to answer is: * Does probiotic supplementation result in improvements in the primary outcome measure of vulnerability and sensitivity to depression, as well as secondary measures of rumination, hopelessness/suicidality, acceptance/coping, aggression, control, and risk aversion? * Does probiotic supplementation improve accuracy and response times in executive function and working memory, measured by the Task Switching Task (TST) and n-back task? * Is probiotic supplementation associated with an increased P300 amplitude and shorter P300 latency compared to baseline measures during the n-back task, in parietal and frontal lobe regions, with more pronounced effects in the 2-back task? * Is probiotic supplementation associated with changes in alpha and theta band activity and symmetry, particularly after completing a demanding working-memory task?
Interventions
DIETARY_SUPPLEMENTEcologic® Barrier
Ecologic® Barrier (1x1010 CFU/day).
DIETARY_SUPPLEMENTPlacebo powder
Matched placebo
Sponsors
University of Reading
Winclove Probiotics B.V.
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Intervention model description
Double-blind, placebo-controlled, randomised control trial.
Eligibility
Sex/Gender
ALL
Age
25 Years to 40 Years
Healthy volunteers
No
Inclusion criteria
* Mild to moderate depression symptoms (BDI-II 12-28) * Males and females * Age range will be 25-40 years * Right-handed participants only (required for EEG)
Exclusion criteria
* Taking antidepressants (up to 2 months prior to inclusion) * Undergoing psychological treatment in the form of counselling, therapy or similar (up to 1 month prior to inclusion) * Any diagnosed chronic medical condition (e.g. diabetes) or psychiatric illness. * Use of antibiotics or laxatives (up to 3 months prior to inclusion) * Use of probiotics and/or prebiotics (up to 1 month prior to inclusion) * Enrolled in any other clinical trial (up to 1 month prior to inclusion) * Following restrictive and/or unbalanced diets * Smoking * Continuous use of a weight-loss medication for more than one month prior to screening * Significant gastrointestinal conditions affecting absorption, including but not limited to: inflammatory bowel disease; total colectomy or bariatric surgery; irritable bowel disease; end-stage renal disease; active cancer or cancer treatment within the past three years
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Leiden Index of Depression Sensitivity - Revised (LEIDS-R) vulnerability/sensitivity for depression. | Baseline and 16 weeks | A standardised measure of cognitive reactivity. This questionnaire consists of 34 items, in which participants rate on a scale from 0 to 4, how strongly they feel each statement relates to them when they feel somewhat sad. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Leiden Index of Depression Sensitivity - Revised (LEIDS-R). The following subscales are of interest: rumination, hopelessness/suicidality, acceptance/coping, aggression, control, and risk aversion. | Baseline, 24 hours, and 16 weeks | A standardised measure of cognitive reactivity. This questionnaire consists of 34 items, in which participants rate on a scale from 0 to 4, how strongly they feel each statement relates to them when they feel somewhat sad. |
| Beck Depression Inventory (BDI-II) | Screening, baseline, 24 hours, and 16 weeks | A robust tool consisting of 21 items used to measure the severity of depression. It focuses on symptoms experienced in the last 2 weeks, such as cognitive and affective symptoms. |
| Mini-International Neuropsychiatric Interview (MINI) | Baseline, 24 hours, and 16 weeks | A short diagnostic interview designed to screen for 17 psychiatric disorders and the risk of suicide. |
| Rumination Response Scale (RRS) | Baseline, 24 hours, and 16 weeks | A self-report questionnaire measuring the tendency to focus on negative thinking, distressing symptoms, and their causes when people feel down, sad, or depressed. |
| Neural Activity | baseline, 24 hours, and 16 weeks | P300 event-related potential (ERP) amplitude and latency during the n-back task. Resting-state and active-state alpha and theta power oscillations. An exploratory measure of the N2 ERP may be analysed alongside the P300. |
| Task-switching Task | Baseline, 24 hours, and 16 weeks | This is a measure of executive function and sustained attention. Participants will be shown a circle with 8 equally spaced radii, 2 of which form a bold bisecting line. Numbers are chosen randomly from a set of 1-4 \& 6-9 and displayed sequentially in a clockwise direction. A response of higher or lower than 5 is made for trials below the line, and a response of even or odd for numbers above the line. Accuracy and reaction time (RT) on correct trials, as well as accuracy and RT on trials where there is a 'switch cost' from stimuli moving from below to above the bold line and vice versa, are the main outcome measures. |
| N-back task | baseline, 24 hours, and 16 weeks | This is an executive function and working memory task. There are varying difficulties of this task, but this trial will use the 0-back and 2-back versions. The 0-back task involves participants being shown a sequence of letters and having to respond when the current letter matches that of the previous letter. In the 2-back task, participants will have to respond when the current letter matches the letter from two trials ago. |
| Profile of Mood States short form (POMS-SF) | Baseline, 24 hours, and 16 weeks | This is a condensed self-report questionnaire used to measure changes in mood, assessed across 6 sub-scales (tension-anxiety, depression-dejection, anger-hostility, vigour-activity, fatigue-inertia, and confusion-bewilderment) with 40 total items. A total mood disturbance score is provided. |
| Visual Analogue Scale (VAS) of Positive and Negative feelings | Every day from baseline to the final 16-week time point. | Visual Analogue Scale of positive/negative feelings via a daily assessment. This includes two questions asking participants to rate on a scale from 0 to 100 the extent to which they felt positive or negative feelings. |
| Quality of Life (SF12) | Baseline, 24 hours, and 16 weeks | The Quality of Life (SF12) is a questionnaire which asks for participants' views about their health. This information keeps track of how they feel and how well they can do their usual activities. |
| Gastrointestinal Symptom Rating Scale (GSRS) | Baseline, 24 hours, and 16 weeks | This is a 15-item self-reported questionnaire assessing the severity of gastrointestinal symptoms. It uses a 7-point Likert scale, covering five symptom domains: reflux, abdominal pain, indigestion, diarrhoea, and constipation symptoms. |
Countries
United Kingdom
Outcome results
None listed