Abstract

Abstract: Laughter is a normal and natural physiologic response to certain stimuli with widely acknowledged psychological benefits. However, current research is beginning to show that laughter may also have serious positive physiological effects for those who engage in it on a regular basis. Providers who prescribe laughter to their patients in a structured way may be able to use these natural, free, and easily distributable positive benefits. This article reviews the current medical understanding of laughter's physiologic effects and makes a recommendation for how physicians might best harness this natural modality for their patients.

Keywords: laughter; prescription; lifestyle medicine; treatment

Current research indicates that laughter has quantifiable positive physiologic benefits.

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Laughter is a complex emotional response to one's environment, situation, and stimuli. Studied for many years, it was not generally perceived to have any particular healing effect until 1979, when Norman Cousins published As Anatomy of an Illness. In this book, Cousins described laughter as creating an analgesic effect for pain caused by his ankylosing spondylitis.' Since that time, interest in laughter as a potential therapeutic option has grown, both in popular culture as well as in scientific research, where the field of psychoneuroimmunology attempts to explore the impact of laughter on our physiology and psychology.

Current research indicates that laughter has quantifiable positive physiologic benefits. So far, these benefits have been small and not yet widely corroborated, but in this era of preventative medicine, they indicate that research on laughter is not only timely and useful but also potentially fiscally sound. This is because laughter is (usually) free, and often without side effects. A 2010 review cataloged the available scientific evidence on the physical benefits of both spontaneous and simulated laughter. This article will update and expand on the 2010 review in order to enhance practitioners' general knowledge and understanding of how laughter pertains to medicine. Additionally, we will make recommendations as to how laughter might be incorporated into a lifestyle medicine approach.

What Is Laughter?

"Laughter" and "humor," though often used interchangeably, have different definitions. Humor refers to the stimulus, such as a joke, which evokes a response. In contrast, laughter refers to a physical reaction characterized by a distinct repetitive vocal sound, certain facial expressions, and contraction of various muscle groups. One study identified 5 separate types of laughter:
* genuine ("spontaneous"),
* self-induced ("simulated"),
* stimulated (eg, tickling),
* induced (ie, via drugs),
* and pathological.

Pathological laughter and crying is typically defined as a disorder of emotional expression due to damage of pathways in the cortex and brainstem," and this is distinctly different from the laughter and humor discussed in this article.

Laughter can be experienced both individually, for example, while recalling a particular event, watching television, or reading a book, or socially in groups, for example, participating in a yoga laughter group or sharing stories with friends.


DOI: 10.1177/1559827614550279. Manuscript received December 9, 2013; revised May 9, 2014; accepted May 30, 2014. From the University of California, San Francisco, California (DL); and Harvard Medical School, Boston, Massachusetts (KB, EF). Address correspondence to Elizabeth Frates, MD, Institute of Lifestyle Medicine, Joslin Diabetes Center, One Joslin Place, Boston, MA 02215; e-mail: efraates1@partners.org.
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Copyright © 2014 The Author(s)