DURING the last winter of the Second World War the Dutch were reduced to eating tulip bulbs. Fewer babies than usual were conceived then as the starvation that the women underwent reduced their fertility, and in many cases their ability to ovulate and menstruate. One unexpected finding was that the incidence of schizophrenia in the babies that were conceived and carried in utero over that winter was twice the usual rate.

It is accepted that a person’s genetic inheritance is the most important factor in determining who develops schizophrenia. This is unlikely to be the result of a single gene but the consequence of the inheritance and interaction of different genes. However, it is believed that people don’t directly inherit the disease but have a vulnerability to it. Environmental factors may then induce the changes that lead to it. Recently the BMA has reported that starvation akin to that in the Netherlands in the war afflicted Anhui province of China in 1959-61. The babies carried in utero at this time have twice the expected rate of schizophrenia. So similar were the circumstances in Anhui to the Netherlands and so alike was the incidence of schizophrenia that other reasons for the Dutch phenomenon have been abandoned.

Intra-uterine starvation will have to be added to those factors that are known to have an ability to uncover a latent tendency to schizophrenia. These factors include family history, cannabis smoking, other drug abuse, infection at the time of birth, delivery in the winter months and emotional strain, being a second-generation immigrant, or living up to community and family expectations.

Without these external factors the genetic inheritance might have caused those born with them no more trouble than that accrues to those who are mildly eccentric. Furthermore, they would have had a good chance that their eccentricity would have been compensated for by an above normal intellect and a greater than usual sense of aesthetic appreciation.