Humor therapy-

aka therapeutic humor and sanctioned by the Association for Applied and Therapeutic Humor (yes, this is real), is using the power of smiles and laughter therapy to reduce the impact of disease.   Therapies employed include humorous videos, stories, laughter clowns, raucous simulated laughter, and Laughter Yoga.   In studies, laughter does appear to change the brain chemistry and boost the immune system, in addition to reduction of the impact of depression and anxiety.   There are studies demonstrating laughter therapy reduces pain in radiation dermatitis patients, especially the more severe dermatitis (Onco Targets Ther 2014 Nov 4:7:2053-9).  Benefits of laughter include reduced anger, anxiety, depression, and stress; reduced tension (psychological and cardiovascular); increased pain threshold; reduced risk of myocardial infarction (presumably requiring hearty laughter); improved lung function; increased energy expenditure; and reduced blood glucose concentration. However, laughter is no joke-dangers include syncope, cardiac and oesophageal rupture, and protrusion of abdominal hernias (from side splitting laughter or laughing fit to burst), asthma attacks, interlobular emphysema, cataplexy, headaches, jaw dislocation, and stress incontinence (from laughing like a drain). (BMJ 2013 Dec 12;347:f7274). 

There are not many high level studies using humor therapy and insurances may balk at payment, but in general given the costs being minimal and given materials that are inexpensive, Painbytes gives humor therapy one thumb up.