Scott Alexander refutes Stephen Skolnick's theory that schizophrenia is caused by gut microbes rather than genetics, showing why the evidence better supports schizophrenia being a complex genetic neurodevelopmental disorder. Longer summary

Scott Alexander responds to Stephen Skolnick's theory that schizophrenia is caused by gut microbes rather than genetics. He systematically dismantles Skolnick's arguments by showing that twin concordance rates are exactly what we'd expect from a genetic condition, that microbiological inheritance patterns don't match schizophrenia inheritance patterns, and that the gut bacteria evidence cited was likely caused by antipsychotic medication rather than being causative. He concludes by explaining why schizophrenia is best understood as a complex neurodevelopmental disorder with multiple contributing factors rather than having a single cause. Shorter summary