If, as hypothesized, neuroactive peptides from grain glutens are the major agents evoking schizophrenia in those with the genotype(s), it should be rare if grain is rare. To test this, we analyzed the results of our clinical examinations (e.g., kuru) and observations of anthropologists on peoples consuming little or no grain. Only two overtly insane chronic schizophrenics were found among over 65,000 examined or closely observed adults in remote regions of Papua New Guinea (PNG, 1950-1967) and Malaita , Solomon Islands (1980-1981), and on Yap , Micronesia (1947-1948). In preneuroleptic Europe over 130 would have been expected. When these peoples became partially westernized and consumed wheat, barley beer, and rice, the prevalence reached European levels. Our findings agree with previous epidemiologic and experimental results indicating that grain glutens are harmful to schizophrenics.