Extreme population differentiation, as measured by the F(ST) value, has been suggested as an indicator of recent population-specific positive selection. Elevated F(ST) values indicating high differentiation between continental groups were previously reported on a linkage disequilibrium region in the Neuregulin 1 gene, a gene which has been associated to schizophrenia. In the present study we show evidence that high F(ST) values may not necessarily imply the action of selection, in particular positive selection, neither globally nor regionally, using the example of the NRG1 gene.