research on laughterFor many years, to argue that laughter’s “favorable impact on the mind influences various functions of the body and makes them healthier,” as an American physician named James Walsh did in 1928, in his book “Laughter and Health,” was to make a claim without evidence. No one had investigated the matter, because the medical community in Walsh’s time, and for nearly half a century afterward, held that the human nervous system was entirely cut off from the immune system.

First credible challenge in 1975

This bias was credibly challenged only in 1975, when Robert Ader, a psychologist at the University of Rochester, was trying to learn if rats could be conditioned to associate nausea with saccharin. Ader had given his rats the sweetener along with a drug called cyclophosphamide, to turn their stomachs. But the animals didn’t just become nauseated; they began to die. Strangely, when Ader stopped administering the cyclophosphamide but continued to feed the rats the sweetener, they still died. Cyclophosphamide, he learned, suppresses the immune system, so he contacted an immunologist named Nicholas Cohen, and the two studied the problem further. They concluded that the rats had been conditioned to suppress their immune systems whenever they tasted the sweetener. In other words, their minds were killing them.

laughter researchThe experiments that Ader and Cohen conducted gave birth to a field called psychoneuroimmunology, but their work did not have popular resonance. That changed a year later, when Norman Cousins wrote about his experience with laughter in the New England Journal of Medicine. Turning Ader and Cohen’s inquiry on its head, he asked the medical community, If feelings of physical and mental distress damage the body’s chemistry, then shouldn’t positive ones rehabilitate it? “Is it possible that love, hope, faith, laughter, confidence, and the will to live have therapeutic value?” Cousins asked. “Do chemical changes occur only on the downside?”

Cousins, who was the editor of the Saturday Review, had travelled to the Soviet Union in 1964, and while he was there, he said, he experienced intense stress and severe pollution. As a result, he concluded, he suffered from adrenal exhaustion, which in turn triggered ankylosing spondylitis, a painful degenerative disease of the joints. After his doctor told him that he had a one-in-five-hundred chance of full recovery, Cousins checked himself out of the hospital and into a hotel room, took huge doses of Vitamin C, and watched “Candid Camera” and the Marx Brothers. There he made “the joyous discovery that ten minutes of genuine belly laughter had an anesthetic effect and would give me at least two hours of pain-free sleep.”

Laughter, Cousins claimed, helped cure his chronic ailment. In 1979, he wrote a best-selling book about his experience, titled “Anatomy of an Illness, as Perceived by the Patient,” and began to teach at U.C.L.A.’s medical school. The book attracted thousands of supporters, but also a number of skeptics. Florence Ruderman, a sociologist of medicine at Brooklyn College, writing in Commentary, took apart much of his story in a careful analysis. Ader and Cohen had demonstrated that the immune and nervous systems were linked, but Cousins was arguing something different, something unproved: that the link could be exploited as a cure. Even if positive emotions were physically beneficial in the long term, Ruderman asked, “is the will to live so easily manipulated, so dependent on trivial, superficial agencies?”

Cousins set out to prove his story. In 1988, he contacted two scientists, Lee Berk, a doctor at Loma Linda University, in Southern California, and William Fry, a psychiatrist at Stanford, after he heard that they “were dabbling in laughter.” Berk and Fry had run an experiment to learn whether laughter dampened the production of cortisol, a hormone that naturally suppresses immune function. Fry watched episodes of “Laurel & Hardy” and “Abbott & Costello,” and Berk sampled his blood. As Fry laughed, it appeared, his cortisol levels decreased. Cousins gave them a grant to do a more formal study, and, along with six other researchers, they conducted the experiment with five laughers and five other subjects who were used as controls. The results were similar, and Berk and his collaborators published them in the American Journal of the Medical Sciences. “The study has shown objective, measurable, and significant neuroendocrine and stress hormone changes with mirthful laughter,” they wrote, noting that laughter “can reverse or attenuate” hormonal changes brought on by stress. In 2001, Berk released a paper concluding that mirthful laughter increases the production of natural-killer cells, which help the body to fight viral infections and cancerous growths. Subsequent reports by Berk and others argue that laughter can have salutary effects on everything from heart disease to diabetes and allergies.

Source: “The Laughing Guru” by Raffi Khatchadourian

Why 1985 changed everything

It wasn’t until 1985 that research by neuropharmacologist Candace Pert, of the National Institutes of Health at Georgetown University, revealed that neuropeptide-specific receptors are present on the cell walls of both the brain and the immune system. The discovery that neuropeptides and neurotransmitters act directly upon the immune system shows their close association with emotions and suggests mechanisms through which emotions, from the limbic system, and immunology are deeply interdependent. Showing that the immune and endocrine systems are modulated not only by the brain but also by the central nervous system itself affected the understanding of emotions, as well as disease.

Contemporary advances in psychiatry, immunology, neurology, and other integrated disciplines of medicine has fostered enormous growth for PNI. The mechanisms underlying behaviorally induced alterations of immune function, and immune alterations inducing behavioral changes, are likely to have clinical and therapeutic implications that will not be fully appreciated until more is known about the extent of these interrelationships in normal and pathophysiological states. In this context laughter remains an unknown science and we anticipate many revealing findings from upcoming research.

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