“…Communication between the gut and the brain takes place on a number of functional levels, including via neural, neuroendocrine and immunological signalling (Cussotto, Sandhu, Dinan, & Cryan, 2018;Foster & Neufeld, 2013). Indeed, the gut microbiota is regarded as one of the major immunomodulatory influences in the human body (Zhao & Elson, 2018). While the exact aetiological associations between psychiatric illness and the gut microbiota are still not fully understood, altered immune responses may be instrumental in the pathogenesis of brain disorders, including OCD (da Rocha, Correa, & Teixeira, 2008;Turna, Grosman Kaplan, Anglin, & Ameringen, 2016).…”