> Microbiota could influence psychology and thus physiology, or it could directly affect physiology and thus psychology. On maybe it's neither and also both.

> Microbiota could influence psychology and thus physiology, or it could directly affect physiology and thus psychology. On maybe it's neither and also both. Personally I think Physiology vs Psychology is the wrong terminology to use: Psychology's domain is the mind which is a somewhat abstract concept, and usually refers to things in terms of thoughts and emotions. Our "psychology" is an emergent property of our physiology, but to me it seems like the wrong abstraction to use as a reference point when speaking about the pathology of something like Schizophrenia. Rather, what I think we're more concretely talking about is the division between nervous system structure (physiology), and activity (which includes, but is broader than psychology). To me, saying the physiology affects the physiology implies the wrong interpretation: i.e. it would be inaccurate to say that the gut bacteria made rat feel certain emotions or have certain thoughts, and those led to long term structural damage. However, it might very well be the case that the gut biome causes a neural activity pattern which leads to long-term pathological adaptations in nervous system structure. If I had to guess, there's probably not a one-way causal relationship, but these systems likely feed back on each-other in a way which results in the symptomatology we describe as Schizophrenia.