Laughter therapy reduces radiation dermatitis

Jacob Schor, ND, FABNO

January 29, 2015


There are two new and rather serious studies and laughter that I want to tell you about.  The first is a Korean study published November 4, 2014 and the second an Iranian study published earlier this month.


Let’s start with the Korean study that asked whether laughter therapy would reduce symptoms caused by radiation treatments for breast cancer.


This was a prospective, randomly assigned controlled clinical trial in which thirty-seven patients were prospectively enrolled.  To join the study, patients had to have pathologically confirmed unilateral breast cancer, without tumor invasion of the skin, completion of breast conserving surgery with or without adjuvant chemotherapy and treatment with postoperative radiation therapy at least 45 Gy.  Eighteen patients were assigned to the laughter group and the other 19 patients were assigned to the control group. The patients in the experimental group received laughter therapy during radiation therapy. Laughter therapy was started at the onset of therapy and provided twice a week until completion of treatment. Patients in the control group only received radiation without laughter therapy. The women in the experimental group differed significantly from the control group in that they were older, more likely to have diabetes and had larger breasts.  All three of these factors are predictive of worse dermatitis.


The laughter therapy employed in this study consisted of a lecture on the benefits of laughter and group sessions that included active motion “… designed to produce laugher, especially mirthful laughter and self-induced stimulated laugher.”  Each session lasted 60 minutes.  The patients were observed by clinic staff and those, “… who did not mirthfully laugh more than 10 times in each laughter therapy session were excluded from this study.” [talk about pressure!]  Patients who did not “… enjoy the laughter therapy…. Were also excluded.”


A radiation oncologist who didn’t know who was who in the study, graded the severity of the skin reaction to radiation. The patients also provided scores to how much pain they were in from treatment.  Patients were examined at baseline and weekly from the start of radiation therapy until 8 weeks after its completion. 


Key Findings:

Three of the experimental group patients were excluded for not showing up to all the laughter sessions.  Therefore 15 patients in the experimental group and 19 in the control group completed the study and their results were analyzed. 


Maximum grade of radiation dermatitis

Grade                                          laughter group (n=15)                            control group (n=19)

3                                          5 (33.3%)                                                        7 (36.8%)

2                                          5 (33.3%)                                                        9 (47.4%)

1                                          5 (33.3%)                                                        2 (10.5%)

0                                          0                                                                      1 (5.3%)


In the experimental group, radiation dermatitis of grade 3, 2, and 1 developed in five (33.3%), five (33.3%), and five patients (33.3%), respectively. In comparison, in the control group, radiation dermatitis of grade 3, 2, 1, and 0 developed in seven (36.8%), nine (47.4%), two (10.5%), and one patient (5.3%), respectively. The experimental group exhibited a lower incidence of grade 2 or worse radiation dermatitis than the control group (33.3% versus 47.4%).  While the experimental group had a lower incidence of grade 2 or worse radiation dermatitis than the control group (66.7% versus 84.2%), these differences did not reach statistical significance (P-0.053). The mean maximal pain scores in the experimental and control group were 2.53 and 3.95, respectively. The experimental group complained less of severe pain than the control group during RT.


While these numbers look good on paper they did not reach statistical significance, that is it could have been lucky chance that makes it look like laughter therapy worked. 

In both univariate and multivariate analysis the total dose of radiation therapy was significantly associated with severity of radiation dermatitis. [1] 


So what does this mean?

As mentioned these improvements did not reach statistical significance, so why am I writing about this?  As the authors point out, “… laughter therapy does not require large amounts of time or money and the side effects of laughter therapy are very limited, so we suggest that laughter therapy can be implemented easily and cost-effectively as complementary therapy in patients with breast cancer without confirmation of our favorable results.”  This is one of those, ‘it won’t hurt, it might help’ situations where the potential benefits outweigh the potential drawbacks.  So it is still worth doing.


Kimata has reported that laughter has significant impact on a number of skin pathologies in particular atopic dermatitis.  In Kimata’s earlier studies, funny videos, Charlie Chaplin and Mr. Bean, were used to trigger laughter.  In this current trial, laughter was self-induced; the authors believe that the brain responds the same to both self-induced and externally stimulated laughter.  This idea that all laughter has the same effect though is still just an assumption.[2]  


Laughter up-regulates the genes that control natural killer cells.[3]    This increase in natural killer cell activity associated with this up-regulation appears to be more related to how much the subjects enjoyed the movie rather than the intensity of the laughter viewing provoked, that “…. the experiential aspects of laughter rather than with the expressive aspects” [4] , raising the question as to why the authors of the current radiation study chose to exclude experimental subjects who were inadequately mirthful in appearance.



A study conducted last year in Iran and published in January 2015 reports that laughter therapy was associated with improvements in, “… factors such as general health (P=0.001), somatic symptoms (P=0.001), insomnia and anxiety.” This was a randomized controlled trial that had enrolled 72 senior citizens who attended events at a senior center.  Half were enrolled into an experimental laughter group and half served as controls.  Data were collected using a General Health Questionnaire. The experimental group attended laughter therapy programs consisting of 90-minute sessions twice a week for 6 weeks.[5] 


Laughter may not have been definitively proven to reduce radiation dermatitis but as it has clear benefit for general health, it still seems prudent to encourage this therapy.


Few patients have easy access to the sort of ‘laughter therapy sessions’ employed in these trials but most, if not all, do have access to online videos and movies these days.  The later may be as if not more effective.  In our practice we encourage patients to watch something online that makes them laugh for 30 minutes a day.  We also encourage them to engage regularly in the rather old fashioned practice of telling jokes. 



Our experience is that laughter therapy does actually have side effects; patients who actively utilize this therapy appear to be happier and have an easier time getting through all of their therapies.  This might not be statistically significant all of the time, but it is clinically significant.



1. Kong M, Shin SH, Lee E, Yun EK. The effect of laughter therapy on radiation dermatitis in patients with breast cancer: a single-blind prospective pilot study. Onco Targets Ther. 2014 Nov 4;7:2053-9. doi: 10.2147/OTT.S72973. eCollection 2014.


2.   Mora-Ripoll R. The therapeutic value of laughter in medicine. Altern Ther Health Med. 2010 Nov-Dec;16(6):56-64.


3.  Sakamoto S, Ishii H, Murakami K. Hayashi T, Tsujii S, Iburi T, Tamanaha T, et al. Laughter up-regulates the genes related to NK cell activity in diabetes. Biomed Res. 2007 Dec;28(6):281-5.


4.  Takahashi K, Iwase M, Yamashita K, Tatsumoto Y, Ue H, Kuratsune H, Shimizu A, et al. The elevation of natural killer cell activity induced by laughter in a crossover designed study. Int J Mol Med. 2001 Dec;8(6):645-50.


5.  Ghodsbin F, Sharif Ahmadi Z, Jahanbin I, Sharif F. The effects of laughter therapy on general health of elderly people referring to jahandidegan community center in shiraz, iran, 2014: a randomized controlled trial. Int J Community Based Nurs Midwifery. 2015 Jan;3(1):31-8.