From what I understand about Schizophrenia, I would expect limited potential here at best. The schizophrenic brain is structurally different: for instance the hippocampus of schizophrenic people is disorganized, and schizophrenic people have less gray matter than neurotypical people.
It's plausible that to some degree these changes could be reversed to some degree long term of they're the result of a tonic stress from the gut biome, and it's also possible that acute schizophrenic episodes could be ameliorated if it turns out they're triggered by the gut, but it's highly unlikely that replacing the gut biome of a schizophrenic person would give you a neurotypical person.
The other thing about schizophrenia is that people usually develop the disorder in their late teens or early 20s with an acute episode. If there is indeed a link to gut bacteria, and if you could identify pre-symptomatic, high-risk individuals, I would imagine this could create a very compelling vector for preventative treatment.
Even if correlation doesn’t imply causation maybe there’s that link in this case as they have done a controlled experiment. They seem to just have stopped short of claiming that schizophrenia is caused by a bacterial gut infection. I wonder why they didn’t claim that?
Probably because it's only a comorbidity. We seem to want easy answers to all these question but the reality is that humans are complex organisms. Having one issue (i.e. an infection) without another (i.e. some specific genetic corruption) will not result in the individual developing a disease however the combination of 2 or more factors results in the development of a disease.
People with schizophrenia get put on anti-psychotic medication. One of the side-effects is significant weight gain. It's likely that this weight gain is affecting gut-microbiome.
