Clayton's
multiple symptoms
of digestive dysfunction (nausea, diarrhea, anal itching, sensitive stomach) were the result
of treatment for his many infections
with frequent
courses of antibiotics, which provided a gut environment conducive to the development
of pathogenic flora and yeast overgrowth.
The delicate balance between the human microbiome and the development
of psychopathologies is particularly interesting given the ease
with which the microbiome can be altered by external factors, such as diet, 23 exposure to antimicrobials24, 25 or disrupted sleep patterns.26 For example, a link between
antibiotic exposure and altered brain function is well evidenced by the psychiatric side - effects
of antibiotics, which range from anxiety and panic to major depression, psychosis and delirium.1 A recent large population study reported that treatment
with a single
antibiotic course was associated
with an increased risk for depression and anxiety, rising
with multiple exposures.27 Bercik et al. 28 showed that oral administration
of non-absorbable antimicrobials transiently altered the composition
of the gut microbiota in adult mice and increased exploratory behaviour and hippocampal expression
of brain - derived neurotrophic factor (BDNF), while intraperitoneal administration had no effect on behaviour.