Effects of Probiotics on Mood
Condition: Depression, Anxiety
MeSH terms: Depression
Study type: Interventional

Summary: 
      Recent demonstration that probiotics administration has positive effects on depressive
      feelings in healthy populations suggests its possible role as an adjuvant therapy for
      depression in clinical populations and as a non-invasive strategy to prevent depressive
      feelings in healthy individuals. The present study extends current knowledge on the
      beneficial effects of probiotics on psychological well-being, as measured by changes in mood
      (e.g., depression, anxiety, cognitive reactivity to sad mood), personality dimensions, and
      quality of sleep, which have been considered as related to mood. For this double-blind,
      placebo-controlled study healthy volunteers pseudo-randomly assigned to an experimental or
      control group assumed a daily dose of probiotic or placebo, respectively, for 6 weeks. Mood,
      personality dimensions, and sleep quality were assessed four times (before the beginning of
      the study, at 3 and 6 weeks, and at 3 weeks of washout).
    

Detailed description: 
      A. THEORETICAL BACKGROUND The intestine and the brain are intimately connected with each
      other through the gut-brain axis, which involves bidirectional communication between the
      nervous, endocrine and immune systems. In the last years, it has become increasingly evident
      that this communication implies also interactions with the intestinal bacterial flora, which
      releases immune activation and other signalling molecules that may play a major role in the
      regulation of the brain and human behaviour. For instance, the microbiota produces
      neuroactive substances and their precursors (e.g. tryptophan) that may reach the brain
      through the endocrine and autonomous nervous system. Recently, the interest has been focused
      also on the cognitive field. Indeed, there is experimental evidence that bacterial products
      may positively influence cognitive functions, such as spatial memory and problem-solving
      abilities. Moreover, probiotics seem to exercise influence on mood, anxiety and depression,
      opening new therapeutic prospects. A recent trial showed that four weeks of taking probiotics
      (Bifidobacterium bifidum W23, Bifidobacterium lactis W52, Lactobacillus acidophilus W37,
      Lactobacillus brevis W63, Lactobacillus casei W56, Lactobacillus salivarius W24, Lactococcus
      lactis W19 e W58) led to an improvement in mood, fostering reduction in negative thoughts.

      B. THE PURPOSE OF THE RESEARCH PROJECT The primary goal of the trial is to investigate the
      effect of probiotics on depression. Moreover, it will assess also effects on anxiety and
      other personality traits in healthy young students. The trial intends also to investigate
      whether probiotics may influence the quality of sleep and bowel habits. The trial will be
      placebo-controlled, randomized, pre- and post-intervention, double-blind designed
      (investigator and participants). In the light of the several end-points examined, the
      statistical analysis will be of explorative type.

      The collection of faecal samples will allow, in case of finding any effects of the
      administered product on mood, to go back to any microbial components that have changed in
      individuals following the treatment. Monitoring (see below) the normal feed and physical
      habits of the individuals will allow to check the possible effect of these confounding
      factors on the parameters measured in the trial.
    

Intervention name(s): Bifihappy; Placebo
Intervention type(s): Dietary Supplement; Other
Intervention description(s): During the six weeks of treatment, the experimental group will take daily doses of 2,5 g with a concentration of 4x109 CFU/sachet of a mixture of lyophilised probiotic strains of the following species:
Lactobacillus fermentum
Lactobacillus rhamnosus
Lactobacillus plantarum
Bifidobacterium longum; During the six weeks of treatment, the experimental group will take daily doses of 2,5 g of maltodextrin
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: The trial design is parallel, with two groups (experimental group and control group) and four evaluation sessions at intervals of three weeks (T0wk = baseline, T3wk = intermediate, T6wk=final and T9wk = follow-up).
Masking: Double (Participant, Investigator)
Primary purpose: Treatment