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.
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.