Although both syndromes persist into adulthood, autism is usually apparent before the age of three, while Asperger's manifests a few years later. In most cases, there is more engagement in activities and friendships and, in contrast to autism, people with Asperger's syndrome have normal intellectual functioning.
Pioneering work by Elizabeth Austin, a psychologist at the University of Edinburgh, found that relatives of those with autism are unusually aloof, tactless, shy, undemonstrative, hypersensitive, anxious, impulsive, irritable, eccentric and rigid. She also found that students studying "hard" science and those with one or both parents in a scientific occupation scored higher on autism spectrum questionnaires.
But in his new book, psychiatrist Michael Fitzgerald argues that Asperger's is just as likely to be found in those who do well in the arts. In The Genesis of Artistic Creativity: Asperger's syndrome and the Arts (Jessica Kingsley Publishers), he puts forward a novel argument that, in many cases throughout history, artistic creativity is linked with the syndrome. He assembles biographical sketches of outstanding writers, philosophers, musicians and painters, including George Orwell, Mozart and Andy Warhol, and asks whether the multiplicity of odd personality traits and behaviour are indicators of Asperger's. For example, there are the eccentric breakfast habits of the American novelist Herman Melville - he badgered cooks about the strength of his coffee and the consistency of his oatmeal - or Simone Weil (a French philosopher), who displayed repulsion for most forms of physical contact throughout her life.
The recurrent sense of tragedy in these lives raises an even deeper question: why suffering and struggle seem to characterise the reach for greatness. It's almost as if genius never naturally arises out of normal humanity, but despite it. The personality features which make people academically successful often mean problems in later life. For this reason, high-flyers might need as much help at school as underachievers if their lives are to avoid the misery catalogued in Fitzgerald's book.
Dr Raj Persaud is Gresham professor for public understanding of psychiatry, and director of the Centre for Public Engagement, King's College London.
His latest book is The Motivated Mind (Bantam Press). Email: firstname.lastname@example.org