Effects of a probiotic supplement on anxiety and mood balance in adults
LE3 .A278 2017
Master of Science
Recent research has implicated the gut-brain axis (the link between the gut microbiome and brain functioning) as a potential factor in the etiology of anxiety and negative mood. It has been demonstrated that disturbances in the gut microbiome can produce anxiety-like symptoms in mice, and that probiotics can restore balance to the gut microbiome while also positively impacting behaviour. A few studies have extended these findings to humans with mixed results, highlighting the need for more research. The current study examined the effects of probiotics (L.helveticus and B.longum) on symptoms of anxiety and low mood in adults. Participants (n=110) consumed a probiotic or a placebo for five weeks. The mood and anxiety outcome measures included the Profile of Mood States (POMS-2), Symptom Checklist-90-Revised (SCL-90-R), Anxiety Sensitivity Index (ASI-3), Hospital Anxiety Scale (HADS-A), Hamilton Anxiety Rating Scale (HAM-A), and State Trait Anxiety Inventory (STAI), completed pre and post intervention. Participants in the probiotic condition improved significantly on the Phobic Anxiety subscale of the SCL-90-R, compared to the placebo condition. However, overall, both the probiotic and placebo groups improved significantly on most measures of anxiety and mood, with little difference between conditions. Exploratory analyses revealed non-significant trends that were in the hypothesized direction; specifically, participants in the probiotic group who were also taking psychotropic medication or seeing a mental health professional (a small subsample of the participants) showed greater improvements in anxiety and mood symptoms than those in the placebo condition. Further research examining probiotics as a supplementary treatment to more conventional treatments is needed to confirm these observations.
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