Manuela Martinez and her colleagues were intrigued. Why was it that women who had suffered domestic violence seemed more prone to outbreaks of cold sores?
On the surface there appeared to be no connection between the physical and emotional abuse they suffered and the herpes infection that broke out on their lips. To try to find a link, they carried out a detailed profile of the saliva of a group of 74 survivors of abuse and compared it to a similar analysis of other women. They found that the abused women had far fewer immune-system compounds able to neutralise the virus. Their levels of antibodies to the virus were also lower. "Our findings confirm that the stress associated with partner violence could impair health by increasing the likelihood of viral reactivation and reducing the ability to suppress virus proliferation," says Dr Martinez, of the department of psychology at Valencia university.
The findings are part of a new and increasing body of evidence showing that the mind, personality and outlook can influence the development and progress of disease. New research, some of it being reported at an international conference on psychosomatic medicine this month, shows that the mind can have an effect on many conditions, from arthritis to cancer and heart disease.
Although Western medicine is still largely based on the paradigm that the mind and body are separate from one another, there is increasing evidence to the contrary. Such a mind-body connection has been hinted at down the centuries, but most of the evidence until now has been anecdotal or inconclusive. But a revival in interest in the mind-body link has triggered a wave of new research. Doctors in Holland who investigated heart disease treatments in almost 1,000 people found that patients with so-called type-D personalities - negative types who have difficulty communicating their emotions - were four times as likely to have heart problems. The same findings have now emerged from at least two other studies.
At Ohio State University, scientists have established that there is a mind-body connection in wound-healing. Their studies found that animals' skin wounds healed twice as quickly when they had social contact with other animals. "Stress delays wound-healing, and social contact helps counteract this delay," says Dr Courtney DeVries, who led the study.
And psychologists at Eastern Michigan University studied the outcome of bone-marrow transplants and found increased rates of survival among patients who were more defiant, better adjusted, and less depressed. "This first large-scale study provides evidence that psychosocial variables can affect survival," say the researchers.
The links don't stop there. Doctors in the UK and Germany looked at 1,300 elderly men and women over 10 years, and found a connection between personality and cancer deaths. "The results justify belief that certain types of cancer may be related to specific stress and personality factors," say the researchers. A Japanese study based on more than 30,000 people concluded that personality may affect mortality rates among cancer and cardiovascular disease sufferes. A second study found that skin cancer patients who had group therapy had higher levels of immune-enhancing cells. And in Los Angeles, scientists at the Digestive Diseases Research Center believe that the mind can even bring about chronic heartburn. "The presence of a severe, sustained life stress during the previous six months significantly increased heartburn symptoms during the following four months. As with other chronic conditions like irritable bowel syndrome, heartburn severity appears to be responsive to major life events," they say. …