Agatha Christie suffered from Alzheimer’s

TORONTO - It is official: famous mystery novelist Agatha Christie suffered from Alzheimer’s.

Two Toronto university professors have finally proved what many biographers of the world’s top mystery novelist have hinted at: that she suffered from mental illness.

In fact, this research by professors Ian Lancashire and Graeme Hirst on Christie’s mental illness has landed them the top spot in the New York Times’ 9th Annual Year in Ideas.

Lancashire, who is a professor of English, and Hirst, who is a computer scientist, have combined humanities and science to give conclusive proof of Christie’s Alzheimer’s-related dementia during the final years of her life.

As part of their research, the two professors digitised 14 of her novels and used textual analysis software to determine the richness and size of the vocabulary used, as well as phrases often repeated and an increase in the use of indefinite words, an indicator of the disease, a statement by the university said Wednesday.

Their research showed that her final two books use a much smaller vocabulary than her earlier works, with differences as large as 31 percent. Her other later works compared with her last two volumes also show a much richer vocabulary.

They published their results in a paper titled “Vocabulary Changes in Agatha Christie’s Mysteries as an Indication of Dementia” to statistically prove their point.

“This publicity - and the honour it bestows - reflects a hope that an aging society has for ways to detect Alzheimer’s disease, a human scourge, earlier than possible now,” said Lancashire after the honour by the New York Times.

He said: “People in all walks of life can understand, and even become conscious of, a change in their personal language. People have a horde of e-mail or blog entries now that go back some years.

“The simple vocabulary measures used in the poster, the graph and the brief paper can be grasped and applied by anyone, privately, non-invasively. The findings astonished me when I found them two years ago. If the N.Y. Times recognition brings more medical researchers to study language, I will be delighted.”

He said their research and recognition highlight the importance of interdisciplinary research in future and the role the humanities can play in scientific research projects.

“At Toronto, the New York Times’ notice highlights the deep strength of this university in interdisciplinary research. Even English professors may have a role to play in practical research of broad public interest,” the Canadian professor said.

“I could not have presented and interpreted my findings properly without the collaboration of Graeme Hirst in computational linguistics and Regina Jokel at Baycrest. I am so fortunate to work in a team now with these colleagues and Graeme’s student Xuan Le,” he added.

The two professors will now examine the writings of the ageing mystery novelist P.D. James and mystery writer Ross MacDonald who is known to have suffered from Alzheimer’s disease.