There was time, when religion was dominant, that the way to make sense of otherwise seemingly inexplicable conditions such as major mental illnesses - schizophrenia and manic depression, for example - was to suggest that sufferers had some inner path to God, that they were holy fools, seers, visionaries. In these more secular days, when art has replaced religion, experts suggest that mental illness and creativity are crucially linked. In the United States, Kay Redfield Jamison, in a series of books, has argued persuasively for a significant link between manic depression and artistic creativity. In this latest book on the subject, David Horrobin suggests, not quite so convincingly, that a "touch of schizophrenia" is associated with exceptional artistic and scientific abilities.
Horrobin's argument is more radical than Jamison's. Manic depression, after all, is an illness characterised, in its manic expression, by enormous energy, rapid thinking, an extraordinary ability to link disparate thoughts and imaginings, and boundless enthusiasm. It is not too difficult to see that such a mental state, married to high intelligence, could prove highly creative. But schizophrenia, particularly in its most severe forms, is a more psychologically fragmenting and disruptive illness. Thinking is not speeded up so much as fractured. There is a poverty, rather than a plethora, of thinking. Whereas there are plenty of examples of creative artists such as Robert Schumann or, in our own time, Spike Milligan who suffered or who suffer from manic depression, the number of truly creative people who suffer from schizophrenia is minute. Horrobin quotes the example of the Nobel Prize-winning mathematician John Nash, but from the moment Nash's illness developed, his mathematical ability all but evaporated.
Horrobin, however, boldly insists that the genes for schizophrenia are responsible for most of the religious sense, most of the technical and artistic creativity and most of the leadership qualities of modern human beings. On occasion, such exceptional ability is manifested by individuals, such as John Nash, who carry all the genes necessary for schizophrenia to appear. More commonly, however, it is manifested by individuals, usually close relatives of people with schizophrenia, who carry just some of the genes and hence do not themselves suffer from schizophrenia, but show so-called "schizotypal" personality characteristics such as pedantry, dogmatism, magical thinking and emotional coldness. Horrobin picks out Isaac Newton as just such an individual, given that Newton was not just a man of the utmost creative brilliance, but someone obsessed with alchemy, the occult and secretiveness, and given to paranoid feuding and social withdrawal.
So is there evidence suggesting that creative people are more likely to be schizotypal in character and more likely to have close relatives showing all the signs and symptoms of schizophrenia? Swift, Wittgenstein, Joyce, Tennyson, Shelley, Huxley, Einstein, Kafka and Wagner are among the many names in Horrobin's list of creative "schizotypal" greats, but the problem is that close examination of any one of these individuals leads one to question the definition of schizotypy, rather than grant Horrobin his argument. The mental disorders and eccentricities of the individuals selected stretch elastically to enable the thesis to survive. Horrobin has to blur the distinctions carefully made elsewhere between schizophrenia, manic depression, schizotypal personality and even psychopathy, so that his argument becomes not so much a case of schizophrenia shaping humanity as mental eccentricity and abnormality shaping humanity.
Horrobin is unabashed, and embarks on an engaging and plausible argument - founded on insights from evolution, genetics, anthropology and nutrition, propounded with gusto, and preoccupied with the importance of certain fats in brain evolution and the abnormal function of such fats in the genesis of schizophrenia. He argues that the development of such human abilities as upright walking, speech and consciousness is due to an explosion in the profusion and richness of the fat-rich connections between the nerve cells of the brain. This crucial development not merely produced brains of enormously enhanced power, it made us human. But, insists Horrobin, it also gave mankind the condition that we know as schizophrenia. These brain fats hold the key to the human brain's incredible ability to make imaginative connections, to be creative. He leaps from family studies of the transmission of schizophrenia to the mutation of genes involved with fat metabolism in brain tissue, links the industrial revolution and its "dramatic increase in saturated-fat consumption" to our "present frantic, enormously creative yet enormously destructive society", and concludes that, without schizophrenia, we can be neither human nor creative. While I greatly enjoyed his arguments and the colour and enthusiasm with which he develops them, I remain unconvinced. Schizophrenia is not all that uncommon. Add in manic depression and certain personality and behavioural traits and it becomes difficult to find an individual, creative or not, who does not have a close relative with one or more of such conditions and/or traits. Studying and listing the oddities and eccentricities of creative people is all very well but, to sustain a convincing argument, studying the rest of us would help. Jamison and others have provided some convincing evidence that there is a link between certain kinds of creativity and manic depression. Horrobin tries to do the same for schizophrenia; but, for all his intellectual pyrotechnics, he fails.
Anthony Clare is clinical professor of psychiatry at Trinity College, Dublin