But Seriously Folks, Laughter Isn't Always Funny

Giggles and guffaws can lift our mood and ease stress. But inappropriateoutbursts can be a sign of some rare medical conditions.Tumbling puppies. The latest YouTube making the rounds. Will Ferrell on thebig screen. All can provoke the flexing of facial muscles and respiratorycontractions that amount to a laugh. Genuine laughter (and possibly evenforced laughter) may be, if not the best medicine, then a pretty good one.But laughter sometimes has a more somber side.Back in the '60s, now-emeritus Stanford psychiatry professor Dr. William Fryembarked on a research agenda that would ultimately help demonstrate thatlaughing was good for human health. Among other things, Fry showed that aminute of hearty laughter elevated the heart rate as much as 10 minutes on arowing machine did.Norman Cousins, a magazine editor who later joined the faculty of themedical school at UCLA, popularized the healing effects of laughter in his1979 book, "Anatomy of an Illness." Cousins had been diagnosed with arheumatic disease called ankylosing spondylitis - and treated himself bytaking daily doses of vitamin C and dosing himself with hearty helpings ofchuckles (he was especially fond of watching the Marx Brothers).Cousins went on to become an eloquent advocate for holistic medicine ingeneral and the therapeutic effects of laughter in particular. But althoughhe claimed that laughter cured him, not all observers were convinced it wasthe giggles that did the trick.Laughter came under increasing clinical scrutiny in the years that followed.Studies in the 1980s and 1990s showed that chortles and whoops can improvemood, mitigate stress and lessen the effects of depression and anxiety.Other studies suggested why this was. Chuckling, it turns out, elevateslevels of endorphins (painkilling chemicals produced by the brain).Following a hearty laugh, blood pressure and heart rate drop, and the bodyrelaxes.In recent years, Loma Linda University researchers have found that laughterincreases the production of some immune cells while spurring others intoaction; it also appears to reduce levels of the immune-depressing stresshormone cortisol.But laughter has a dark side too. Laughing allegedly brought on the strokethat killed British novelist Anthony Trollope and caused temporary blindnessin a Massachusetts man cracking up at an episode of "Seinfeld" - mysteriousoccurrences that still have scientists perplexed.Inappropriate laughter is also a hallmark of a handful of rare medicalconditions, an indication that something has gone awry somewhere in thebrain.The lobotomies commonly performed in mental hospitals in the 1940s and 1950soccasionally resulted in a new problem for the patients: fits ofuncontrollable and involuntary laughter, brought on by damage to the brain'sfrontal lobe, the seat of voluntary movement and emotion.A rare developmental disorder known as Angelman Syndrome is accompanied byseizures, jerky movements and paroxysms of inappropriate laughter.A type of epilepsy, known as gelastic epilepsy, is also characterized byfits of out-of-place laughter; "gelos" is the Greek word for laughter.Kuru, a now very rare degenerative brain disease affecting the natives ofNew Guinea, and a related disease called Creutzfeldt- Jakob disease, are bothaccompanied by seemingly unprovoked spells of laughter. Both diseasesinvolve such extensive brain degeneration (caused by infectious proteinsknown as prions) that scientists are still unsure how, precisely, they causesuch pathological laughter.Diseases aren't the only cause of out-of-context laughter: Toxic substancescan bring it on too. Manganese poisoning once caused clumsiness andchuckling in workers who mined the mineral for a living. A deadly herbnative to the island of Sardinia causes the same strange laughter beforeresulting in the death of its still-smiling victims.And then, of course, there are the less-toxic, laugh-inducing gases nitrousoxide and ether. Nitrous oxide, commonly known as laughing gas, first becamea popular recreational drug back in the 19th century. In 1844, an astutedentist decided the feel-good gas might have a place in his clinic too. Totest his hypothesis, he had one of his own wisdom teeth extracted whileintoxicated. Painless dentistry for all of his patients (and also others)ensued.The conditions that cause inappropriate laughter aren't communicable, butlaughter often is. Humans laugh when they hear laughter (recall the sitcomlaugh track), and laughter spreads easiest in large groups of people.Sometimes it spreads like wildfire. In January 1962, three teenage girls ina school in what is now Tanzania erupted into uncontrollable hysterics. Soonmore than half the girls in the school were convulsing with giggles, and thestaid teachers were forced to suspend all classes. The girls took theircontagious laughter home with them, ultimately infecting close to a thousandpeople with guffaws to the point of breathlessness and tears.Something similar happens in some Pentecostal churches in the U.S. today, inwhich pastors infect their congregations with fast-spreading, contagious,whole-body laughter. Not only is laughter likely good for the body; some, itseems, are convinced it's good for the soul.
[NYT]