Research by a Scottish historian could help psychologists and psychiatrists to gain a better understanding of mental illness.
Rab Houston, professor of early modern history at St Andrews University, has carried out a five-year study of mental illness in 18th-century Scotland, examining civil and criminal court records, family papers and asylum documents.
He discovered identifiable conditions such as schizophrenia and manic depression, as well as a stalker, and a woman who wanted a doctor to remove a healthy leg, harbingers of current controversial incidents.
A cross-cultural study of a particular disease across a range of countries can allow medical researchers to strip away "cultural baggage" to discover the essence of the condition, said Professor Houston. A similar investigation of mental illness in the past could result in more effective treatment of these same illnesses today.
But Professor Houston's interest is in the "cultural baggage" that revealed strong evidence of humane treatment, where family and community tried to help people with mental illness rather than incarcerating them.
"The understanding that people have of mental incapacity is a good deal more sensible and sophisticated than you might expect," he said.
"There are maybe 600 people in madhouses at the start of the 19th century, 15 per cent of all those deemed to be insane. People only end up in secure accommodation if they are a danger to themselves and others. The implication is that madness is much more a part of everyday life, and it is possible for ordinary people both to understand the disease and cope with it."
Professor Houston discovered the people were judged mentally incapable by subtle criteria based on standards of social class, age and sex. "Definitions of mental incapacity were based largely on the ability to function in society, rather than what we would regard as an investigation of their psyche," he said.
The definition, even in the courts, was made almost exclusively by lay people, often friends and neighbours, and rarely by the medical profession.
"Now all definition at a formal level is done by doctors, and that may or may not be a good thing. We also have highly developed and expensive social services, so there are the facilities to care for people in an institutional way, and there are drugs. Care in the community is now a dirty phrase, but in the 18th century, care in the community worked, and worked quite effectively."
Madness and Society in 18th-Century Scotland. Clarendon Press, Oxford. Pounds 55.00 ISBN 0 19 820787 5.