Lost in Translation: The Gut Microbiota in Psychiatric Illness

Despite decades of research, and many promising hypotheses, the underlying etiology and pathophysiology of psychiatric illness remains unknown. There is evidence for the involvement of the HPA axis, monoamine neurotransmitters, inflammation, early life events, and the environment, among other factors,1 but, to date, there has not been a unifying theory to connect these different lines of research. Concurrently, there has been burgeoning interest in the role the gut microbiota may play in health and disease. In fact, the gut microbiota influences many of the factors that may be involved in psychiatric illness and is shaped by early life events and environmental factors, including diet, migration, and urbanicity.2 There is now a wealth of animal studies demonstrating that the gut microbiota plays a critical role in modulating the brain and behaviour; however, to date, there has been a paucity of studies looking at the gut microbiota in psychiatric illness. Given the potential for development of preventative and therapeutic interventions targeting the microbiota, it is essential that clinical studies of the gut microbiota in psychiatric illness be performed.