04 August 2005

Schizophrenia linked to mother's diet

A study of Chinese children born before, during, and after a famine in the late 1960s, combined with a prior study of a Dutch famine during WWI, provides evidence that children born to severely malnourished mothers are about 70% more likely to develop schizophrenia.

Researchers are interpreting this as supporting the theory that schizophrenia results from a genetic predisposition, combined with environmental triggers.

Given the devastating nature of schizophrenia, which would give sufferers a very low survival rate, a natural question to ask is why the gene has survived. Many other disease-causing genes have survived because they offer their bearers some benefit — a classic example is sickle-cell anemia. A person with two copies of the sickle-cell anemia gene will get this devastating disease; but someone with only one copy is partly protected from malaria. This is why sickle-cell anemia is today seen in people descended from ancestors who once lived in malaria endemic areas.

What benefit could derive from having some of the genes responsible for schizophrenia? There's a surprising, if speculative, answer:
Researchers into shamanism have speculated that in some cultures schizophrenia or related conditions may predispose an individual to becoming a shaman. Certainly the experience of having access to multiple realities is not uncommon in schizophrenia, and is a core experience in many shamanic traditions. Equally, the shaman may have the skill to bring on and direct some of the altered states of consciousness psychiatrists label as illness.
If this is true, schizophrenia may have survived genetically because the behavior enabled by those genes caused the person to be more valued as a shaman by the society in which they lived — behavior which does not fit well into more modern societies.

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