Recent years have brought growing interest in potential connections between vintestinal microbiota and mental health.
Results from numerous studies indicate a modulatory role of microbiota in brain development and functioning via a complex of neural, endocrine and immune mechanisms related to normal functioning of the brain-gut axis. These findings, in turn, give rise to research into new treatment strategies for psychiatric disorders through modifications of the gut microbiota with the use of a new therapeutic group, i.e. psychobiotics. These are probiotic bacteria which, if consumed in adequate doses, influence the gut-brain axis functioning and consequently the state of patients suffering from mental illness.
The purpose of this paper was to define the current state of knowledge on the potential use of psychobiotics in the treatment of affective disorders. In order to present the analysed issues in a clear and comprehensive manner, the article is divided into the following subsections: (I) Intestinal microbiota: definitions, composition and functions; (II) From probiotics to psychobiotics: a historical perspective; (III) Mechanisms of action of psychobiotics in preclinical studies; (IV) Preclinical studies on the effect of microbiota on behaviour in animal models; (V) Clinical studies on the effect of microbiota on mental state in a group of healthy volunteers; (VI) Possibilities and future prospects for the psycho-biotic-based treatment of affective disorders.
Preliminary study results raise hope that psychobiotics may be an important addition to the psychiatrist’s armamentarium as a therapeutic improving the efficacy of the treatment for affective disorders.