Schizophrenia has become an elusive medical conundrum since it was first described at the turn of the 19th century. Over time, a variety of causal hypotheses have been advanced to explain the spectrum of schizophreniform disorders. This etiological explanation outlines the relationship that obtains between smoking, schizophrenia, and impaired glycometabolism which also includes disruption to the dopaminergic and serotinergic pathways. A possible genetic explanation for this disruption will be identified which links mental illness to a locus of genes contained on the short arm of chromosome 11. These genes are all essential to normal glucose transport which positron emission tomography (PET) scans show is seriously abnormal in schizophrenia. Thus, a redefinition of schizophrenia as 'cerebral diabetes' will be proposed since this term implies a diabetic brain state consistent with PET scans of schizophrenic patients.