Laughter is irrefutably contagious and many times more powerful when shared. A funny situation shared among friends is immensely more enjoyable than when experienced alone. The power of laughter’s contagion is illustrated everywhere from the collective snickers of children in a classroom to the use of television laugh tracks to elicit laughter from the viewing audience.

In his 1979 autobiography, Anatomy of an Illness, Norman Cousins brought the issue of humor therapy to the attention of the medical community. Cases like his, in which laughter therapy brought terminally ill patients to good health, helped popularize the subject. But it wasn’t until 1989—when the Journal of the American Medical Association (JAMA) acknowledged that laughter helps improve the quality of life for patients with chronic illnesses—that laughter therapy was recognized as a legitimate form of treatment, which brings immediate, symptom-relieving effects. This initiated studies around the world, essentially proving that mirth strengthens, and negative emotions like depression and anger weaken the immune system. Today, the effects of laughter are considered a powerful weapon in the fight against AIDS, cancer, and other diseases.

For even the healthiest people, laughter is needed to maintain wellness both mentally and physically. The stress and strain of conflicts and tension around us can compound our everyday concerns, contributing to a rise in anxiety and depression. For overall wellness, laughter therapy takes on biggest responsibility: preventing illness by providing a daily release for the body’s negative energies and allowing us to focus on the positive.