Mental health nurses are being increasingly encouraged to move to a more biologically oriented approach. Authors such as Professor Gournay promulgate the myth that biological psychiatry will soon be able to provide an unambiguous model of the nature of mental disorder. A closer examination of some of the biological research identified by Gournay as moving us closer to this ideal reveals, however, the confused and unconvincing nature of the results so far achieved. In the light of this it seems premature to be advocating wholesale acceptance of the biological model by nursing. Nurses should be made aware of the investigations of the biologists, but, unless they are equipped with the necessary intellectual tools to place such investigations in context, they will continue to be susceptible to the rhetoric of proselytisers such as Gournay.