Depression and bipolar disorder indicate a mood disorder. Beyond classic psychiatric treatments, research is in progress to evaluate the impact of intestinal microbiota on these disorders.
Mood disorders are common: 300 million people in the world suffer from depression and 60 million have bipolar disorder. These disorders cause mental distress that can often be severe, which can lead to suicide. They are the #1 cause of professional and social disability in the world.
Inappropriate stress response
Each individual has their own vulnerability to depression or bipolar disorder, which is in part genetic. As a result, during unpleasant life events, some people experience an excessive response, with overly elevated secretion of the stress hormones cortisol and adrenaline. This situation can lead to nervous exhaustion and favor the onset of a depressive state. Recent research has also documented the role of intestinal flora (microbiota) in these inappropriate stress responses. Indeed in animals, microbiota participates in the regulation of emotions through communication between the intestine and the brain. In the case of dysbiosis (disruptions in the composition of the microbiota), this regulation is less effective and favors the onset of mood disorders.
A new avenue for treatment
Beyond classic treatments (antidepressants, mood regulators, psychotherapy, etc.), a new avenue is opening: rebalancing the microbiota to influence mood. A recent study also showed that taking probiotics daily, a combination of lactobacilli and bifidobacteria, improved mood and reduced the level of anxiety in healthy subjects.
Organisation Mondiale de la santé (OMS), troubles mentaux, avril 2017, http://www.who.int/mediacentre/factsheets/fs396/fr/
Organisation Mondiale de la Santé (OMS), La dépression, février 2017 http://www.who.int/mediacentre/factsheets/fs369/fr/
INSERM, dépression, août 2014, http://www.inserm.fr/thematiques/neurosciences-sciences-cognitives-neurologie-psychiatrie/dossiers-d-information/depression
Cryan JF, Dinan TG. Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour. Nat Rev Neurosci 2012 ; 13 : 701-12.
Messaoudi M, Lalonde R, Violle N, et al. Assessment of psychotropic-like properties of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and human subjects. Br J Nutr. 2011;105(5):755-764.