The purpose of this study is to investigate the effects of a multispecies probiotic on the function of the vagal nerve in patients with major depression and healthy participants in a single-center, randomized, placebo-controlled trial.
After being informed about the study and potential risks, all participants giving written informed consent will be screened for eligibility for study entry and will be randomized in a double-blind manner to receive either a multistrain probiotic or a placebo for 3 months. At entry, 1 week after inclusion, 4 weeks after inclusion and 3 months (end of study) vagal activity will be measured using a 24hr electrocardiogram.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
86
Participants in intervention group receive 2x3g of a multistrain probiotic containing Bifidobacterium bifidum W23, Bifidobacterium lactis W51, Bifidobacterium lactis W52, Lactobacillus acidophilus W22, Lactobacillus casei W56, Lactobacillus paracasei W20, Lactobacillus plantarum W62, Lactobacillus salivarius W24, Lactococcus lactis W19.
Participants in the placebo group receive 2x3 gram of a placebo supplement not containing probiotic strains.
Medical University of Graz
Graz, Styria, Austria
Change of Vagal function
Heart rate variability parameters (logRSA; SDNN)
Time frame: 4 measurements with 24-hr heart rate variability at study entry, one week after, 1 month after and after 3 months
Change of C-reactive protein (CRP)
CRP is measured from serum samples with a Cobas analyzer.
Time frame: 4 time points at study entry, one week after, 1 month after and 3 months (completion of the study)
Change of Interleukine-6 (IL-6)
IL-6 is measured from serum samples with a Cobas analyzer.
Time frame: 4 time points at study entry, one week after, 1 month after and 3 months (completion of the study)
Change of Oxytocin
Oxytocin will be measured from serum samples using ELISA
Time frame: 4 time points at study entry, one week after, 1 month after and 3 months (completion of the study)
Change of Gut microbiome analysis
16S sequencing of gut microbiome samples, gut microbiota composition will be investigated with QIIME2 and characterized in terms of diversity (alpha-diversity, beta diversity) and differential bacterial abundance between time points.
Time frame: 4 time points at study entry, one week after, 1 month after and 3 months (completion of the study)
Change of Body mass index
Weight will be measured with a calibrated scale, height will be measured with a non expandable tape. BMI will be calculated using the formula \[kg/m2\].
Time frame: 4 time points at study entry, one week after, 1 month after and 3 months (completion of the study)
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Mini-international neuropsychiatric interview (M.I.N.I.)
short structured clinical interview which enables researchers to make diagnoses of psychiatric disorders according to DSM-IV or ICD-10
Time frame: at study entry
Change in Hamilton Scale for Depression (HAMD)
Scoring is based on the 17-item scale and scores of 0-7 are considered as being normal, 8-16 suggest mild depression, 17-23 moderate depression and scores over 24 are indicative of severe depression
Time frame: 4 time points at study entry, one week after, 1 month after and 3 months (completion of the study)
Beck Depression Inventory (BDI)
21-question multiple-choice self-report inventory, one of the most widely used psychometric tests for measuring the severity of depression. The rating is as follows: 0-13: minimal depression 14-19: mild depression 20-28: moderate depression 29-63: severe depression
Time frame: Change in 4 time points at study entry, one week after, 1 month after and 3 months (completion of the study)
Change in Pittsburgh Sleep Quality Inventory (PSQI)
The PSQI is used to rate sleep quality. It includes a scoring key for calculating a patient's seven subscores, each of which can range from 0 to 3. The subscores are tallied, yielding a "global" score that can range from 0 to 21. A global score of 5 or more indicates poor sleep quality; the higher the score, the worse the quality.
Time frame: at study entry, after 7 days, after 4 weeks and after 3 months
Change in Adult Attachment Scale
The scale consists of 18 items scored on a 5 point likert-type scale. It measures adult attachment styles named "Secure", "Anxious" and "Avoidant", defined as: * Secure = high scores on Close and Depend subscales, low score on Anxiety subscale * Anxious = high score on Anxiety subscale, moderate scores on Close and Depend subscales * Avoidant = low scores on Close, Depend, and Anxiety subscales
Time frame: at study entry, after 7 days, after 4 weeks and after 3 months
Change in "Wiener Ernährungsprotokoll"
24-hr food recall
Time frame: at study entry, after 7 days, after 4 weeks and after 3 months
Change in International Physical Activity Questionnaire
The IPAQ is a 27-item self-reported measure of physical activity for use with individual adult patients. There are no validated cut-offs.
Time frame: at study entry, after 7 days, after 4 weeks and after 3 months