Schizophrenia 'Helped the Ascent of Man'

Tiny mutations in our ancestors' brain cells triggered mankind's takeover of the world 100,000 years ago. But these changes also cursed our species to suffer from schizophrenia and depression.

This is the controversial claim by biochemist David Horrobin in a new book, The Madness of Adam & Eve: How schizophrenia shaped humanity, to be published by Bantam Press next month.

Horrobin - who is medical adviser to the Schizophrenia Association of Great Britain - argues that the changes which propelled humanity to its current global ascendancy were the same as those which have left us vulnerable to mental disease.

'We became human because of small genetic changes in the chemistry of the fat in our skulls,' he says. 'These changes injected into our ancestors both the seeds of the illness of schizophrenia and the extraordinary minds which made us human.'

Horrobin's theory also provides support for observations that have linked the most intelligent, imaginative members of our species with mental disease, in particular schizophrenia - an association supported by studies in Iceland, Finland, New York and London. These show that 'families with schizophrenic members seem to have a greater variety of skills and abilities, and a greater likelihood of producing high achievers,' he states. As examples, Horrobin points out that Einstein had a son who was schizophrenic, as was James Joyce's daughter and Carl Jung's mother.

In addition, Horrobin points to a long list of geniuses whose personalities and temperaments have be-trayed schizoid tendencies or signs of mental instability. These include Schumann, Strindberg, Poe, Kafka, Wittgenstein and Newton. Controversially, Horrobin also includes individuals such as Darwin and Faraday, generally thought to have displayed mental stability.

Nevertheless, psychologists agree that it is possible to make a link between mental illness and creativity. 'Great minds are marked by their ability to make connections between unexpected events or trends,' said Professor Til Wykes, of the Institute of Psychiatry, London. 'By the same token, those suffering from mental illness often make unexpected or inappropriate connections between day-to-day events.'

According to Horrobin, schizophrenia and human genius began to manifest themselves as a result of evolutionary pressures that triggered genetic changes in our brain cells, allowing us to make unexpected links with different events, an ability that lifted our species to a new intellectual plane. Early manifestations of this creative change include the 30,000-year-old cave paintings found in France and Spain.

The mutation Horrobin proposes involves changes to the fat content of brain cells. 'Sixty per cent of the non-aqueous material of the brain is fat. Humans have bigger heads than chimpanzees because their heads are full of fat.' By adding fat to our brain cells, we were able to control the flow of electrical signals more carefully and make more complex connections within our cortexes.

Our 'schizophrenia inheritance' was 'the single most important event in human history' and marked the break 'between our large-brained, possibly pleasant but unimaginative ancestors, and the restless, creative creatures we are today,' he adds.

This idea was last week described as 'a reasonable hypothesis' by palaeontologist Professor Chris Stringer, of the Natural History Museum, London. 'It is well known there have been key brain cell mutations in our species in our recent past. It is also likely there would have been undesirable side-effects.'

Horrobin points out that schizophrenia is found in every racial group, at a frequency of between 0.7 and 1.0 per cent. However, mankind would initially have been largely unaffected by the disease because our hunter-gatherer forebears ate meat and other fat-rich foods.

These supplied our brain with the chemicals needed to maintain proper mental operation. With the invention of agriculture our diets changed and the fat content of our food altered - making us more vulnerable to mental diseases, says Horrobin.

Many scientists remain sceptical about the ideas of Horrobin, former managing director of Scotia Pharmaceuticals, which made evening primrose oil and other chemicals until it fell into insolvency this year.

Professor Tim Crow of Oxford University agreed genetic changes may have made us vulnerable to schizophrenia. 'The trouble is Horrobin's mechanism does not explain why so very few of us ever develop the disease.'