Research into the genomics of schizophrenia promises much, but so far is resplendent with failures to replicate, and has yielded little of therapeutic potential. Within our bodies resides a dynamic population of gut microbes forming a symbiotic superorganism comprising a myriad of bacteria of approximately 10(14) cells, containing 100 times the number of genes of the human genome and weighing approximately the same as the human brain. Recent preclinical investigations indicate that these microbes majorly impact on cognitive function and fundamental behavior patterns, such as social interaction and stress management. We are pivotally dependent on the neuroactive substances produced by such bacteria. The biological diversity of this ecosystem is established in the initial months of life and is highly impacted upon by environmental factors. To date, this vast quantity of DNA has been largely ignored in schizophrenia research. Perhaps it is time to reconsider this omission.Molecular Psychiatry advance online publication, 7 October 2014; doi:10.1038/mp.2014.93.