There is research on shiatsu happening all around the world looking into its safety and efficacy. See below for studies into effects of shiatsu treatment on headaches, lower back pain, anxiety, stress, pain, sleep quality...
Giuseppe Lanza, Stella Silvia Centonze, Gera Destro, Veronica Vella, Maria Bellomo, Manuela Pennisi, Rita Bella, Domenico Ciavardelli
Published in Complementary Therapies in Medicine Vol 38, June 2018, pp 74-78
"The combination of Shiatsu and physical activity improved depression in AD patients compared to physical activity alone. The pathemechanism might involve neuroendocrine-mediated effects of Shiatsu on neural circuits implicated in mood and affect regulation."
Veronica Villani, Luca Prosperino, Fulvio Palombini, Francesco Orzi, Giuliano Sette
Published in Neuralogical Sciences 2017, online 10 March 2017 Copyright Springer-Verlag Italia 2017
"This article presents the findings from a single-blind, randomised trial investigating the effect of combining shiatsu plus amitriptyline for patients with refractory headaches. Although the combination did not provide any additive/synergistic effect, the shiatsu was superior to amitriptyline in reducing the number of pain killers taken per month. There was no safety concern for shiatsu (alone or in combination)."
Daniel Pach, Mike Piper, Fabian Lotz, Thomas Reinhold, Mirja Dombrowski, Yinghui Chang, Susanne Blödt, Gabriele Rotter, Katja Icke,1 and Claudia M. Witt
Published in The Journal of Alternative and Complementary Medicine, October 2017
"An additional treatment with six tuina sessions over 3 weeks was effective, safe and relatively cost-effective for patients with chronic neck pain.
A future trial should compare tuina to other best care options."
Neil Browne, Fernando Cabo, Donatella Gabrielli, Rumiko Ishii, Diego Robirosa, Rita Serra
Published in European Journal of Integrative Medicine, Volume 8, Issue 4, August 2016, pp 589-590
"Anxiety, stress management and pain scores were the most improved, on average, by two points on the Likert scale. Patients have stated that 'being listened to' and 'being heard were important factors when describing how Shiatsu had helped."
Published in International Journal of Therapeutic Massage & Bodywork, Volume 7, Issue 4, December 2014 pp 23-28
"Zen Shiatsu, a Japanese modality based on traditional Chinese medicine, provided meaningful and positive benefits for a child with autism. This case study offers preliminary evidence for the possibility of Zen Shiatsu providing a viable complementary therapy for alleviating stress in children with Autism Spectrum Disorder, thereby potentially improving the overall health-related quality of life."
Cary A Brown, Geoff Bostick, Leisa Bellmore, Dilesha Kumanayaka
Published in Journal of Integrative Medicine
, Volume 12, Issue 2, March 2014, pp 94-101
"These preliminary findings are promising and future studies exploring the mechanism of action and with stronger control of treatment fidelity are indicated."
Susan LK Yuan MSc, Ana A Berssaneti PhD, Amelia P Marques PhD
Published in Journal of Manipulative and Physiological Therapeutics, Vol. 36, Issue 7, September 2013 pp 436-443
Zoe M Pirie, Nick J Fox, Nigel J Mathers
"This pilot study showed the potential of shiatsu in the improvement of pain intensity, pressure pain threshold, sleep quality, and symptoms impact on health of patients with fibromyalgia. The proposed Shiatsu treatment protocol was feasible and well accepted by the patients."
Published in Complementary Therapies in Clinical Practice, Volume 18, Issue 1, February 2012 pp 37-42
Project for the Systematic Review of the Efficacy, Safety and Efficiency of Traditional East Asian Medicine
"Findings of this single case study suggest that shiatsu is highly valued by patients and GPs, recommending further research into its cost and clinical effectiveness." p. 41
R Fuji, A Ogata, H Tsukayama, T Tokutake (University of Tsukuba), K Tsutan (University of Tokyo)
Andrew F Long, Lisa Edmond, Seamus ConnollyPublished in Complementary Therapies in Medicine, Volume 17, Issue 3, June 2009, pp 168-175
"633 clients provided full follow-up data, a response rate of 67%. A prevalence rate of 12–22 per 100 of client-perceived ‘negative responses’ was found across the three countries. Transitional effects accounted for 82% of all the client-described ‘negative’ responses. Nine clients (1.4% of the total), relating to 10 sets of written comments, reported a negative response that was classified as ‘a potentially adverse event or effect’ that might represent a risk to client safety. None of these clients ceased shiatsu."
Andrew F LongSchool of Healthcare, University of Leeds, December 2007Japan Shiatsu College
Linda H Brady, Kathryn Henry, James F Luth, Kimberley K Casper-Bruett
"... a study of 66 individuals complaining of lower pain. Each individual was measured on state/trait anxiety and pain level before and after four shiatsu treatments. Each subject was then called 2 days following each treatment and asked to quantify the level of pain. Both pain and anxiety decreased significantly over time... These subjects would recommend shiatsu massage for others suffering from lower back pain..."
PE Harris, N Pooley
Published in Complementary Therapies in Medicine, Vol. 6, Issue 1, March 1998, pp 30-35
"It was concluded that efficacy research in shiatsu should focus on musculoskeletal and psychological problems particularly neck/shoulder and lower back problems, arthritis, depression, stress and anxiety."