By: Veronique Mandal Star Health-Science Reporter, Windsor Star
October 9, 2002 Wednesday Final Edition

Geography plays a role in the incidence of schizophrenia, scientists suspect.

American researcher Dr. E. Fuller Torrey discovered that southern Ireland has probably the highest incidence of the disease in the world -- four per cent of the population, compared to one per cent for the rest of the world.

Torrey, executive director of the Stanley Medical Research Institute in Bethesda, Md., says the highest rates were found among the country's poorest people. He ruled out inbreeding as a cause, since successive invasions of Celts, Spaniards, Scots and English ensured a wide genetic mix.

Emigration of the strongest, leaving behind the weakest, was another theory which also does not hold water, according to Torrey, since as early as 1850 a high rate of insanity was reported among the Irish in Massachusetts.

Studies showed higher rates of schizophrenia among the Irish in the U.S. in 1913, 1920 and in the 1940s.

There is also no indication that the rate of schizophrenia is decreasing. Recent figures show an eight-per-cent increase in first admissions for schizophrenia between 1965 and 1974.

One factor being studied is potato consumption. When exposed to light, the potato produces a keloid called solanine which can cause gastrointestinal disturbances and psychotic symptoms, including hallucinations.

Torrey says while it might sound far-fetched, in the 20th century it was proved that many people living in the southern U.S. were spending lifetimes in institutions for a mental illness which turned out to be pellegra, caused by a lack of the vitamin niacin.

Other countries with a high rate of schizophrenia include Croatia, a part of Yugoslavia and some of the Scandinavian nations

In other countries, such as New Guinea, Torrey says schizophrenia is hard to find. Low rates have also been found in Italy and Spain, as well as in most developing countries. Schizophrenia has also been hard to find in remote parts of Africa and Southeast Asia.

Rates are higher in India and Sri Lanka, with studies in India showing that the illness is more common among the upper castes -- those who are more educated and exposed to western technology.

Spud factor: Scientists are investigating a possible link between potato consumption and schizophrenia.