The best medicine: when we laugh, the ensuing endorphin rush makes us feel better. So we can stimulate relief from stress or pain just by having fun

WHAT EFFECT does laughter have on us? When answering this question, people often say such things as: 'It makes me feel good ... I communicate better ... It relieves stress ... I feel happy.' It is amazing that we can experience so wide a range of benefits from such a simple natural reflex.

But researchers have long appreciated that laughter is not so straightforward. Psychoneuroimmunology (PNI)--the discipline that studies the relationship between psychological states and the immune response--reveals that laughter is a complex and health-inducing phenomenon. Investigations into the reflex were given a boost in the 1970s through the experience of Norman Cousins.

A New York journalist, Mr Cousins was diagnosed as having the chronic inflammatory disease ankylosing spondylitis. He was told the condition was progressive and incurable, and eventually he was in such pain that his painkillers became ineffective. What he had noticed, however, was that when he laughed, he felt better. To his astonishment he noted that ten minutes of genuine belly laughter would give him at least two hours of pain-free sleep. He went on to achieve an almost total recovery from an 'incurable' condition and wrote extensively about it.

His groundbreaking story can be read in his own words (Cousins 1979) and provides detailed descriptions of the powerful and previously unexplored benefits that occur through the process of laughing. His writings helped to stimulate our expanding understanding of the beneficial role of endorphins, hormones secreted in the brain and nervous system that activate the body's opiate receptors, causing an analgesic effect.

Endorphins and the pain relief aspect of laughter continue to be investigated. One innovative project is Rx Laughter, an American non-profit research, therapeutic entertainment and health education organisation. Founded in 1998, it is based at the University of California Los Angeles Jonsson Cancer Centre, Mattel Children's Hospital and Neuropsychiatric Institute and Hospital.

Rx Laughter is for children and teenagers in hospital and experiencing pain from cancer, orthopaedic injury, chronic arthritis, severe wounds or burns. While undergoing medical procedures they are shown carefully selected comedy videos from television and films. As the youngsters enjoy the videos, members of the Rx Laughter team explore ways of boosting immune function, speeding up healing, reducing pain and improving their quality of life. These shows are then prescribed as part of individualised...