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Randomised controlled trial of animal facilitated therapy with dolphins in the treatment of depression

BMJ 2005; 331 doi: (Published 24 November 2005) Cite this as: BMJ 2005;331:1231
  1. Christian Antonioli, PhD candidate in psychiatry1,
  2. Michael A Reveley, professor of psychiatry (rev{at}
  1. 1 Department of Health Sciences, Division of Clinical Psychiatry, University of Leicester Medical School, Leicester General Hospital, Leicester LE5 4PW
  1. Correspondence to: M A Reveley
  • Accepted 27 June 2005


Objective To evaluate the effectiveness of animal facilitated therapy with dolphins, controlling for the influence of the natural setting, in the treatment of mild to moderate depression and in the context of the biophilia hypothesis.

Setting The study was carried out in Honduras, and recruitment took place in the United States and Honduras.

Design Single blind, randomised, controlled trial.

Participants Outpatients, recruited through announcements on the internet, radio, newspapers, and hospitals.

Results Of the 30 patients randomly assigned to the two groups of treatment, two dropped out of the treatment group after the first week and three withdrew their consent in the control group after they had been randomly allocated. For the participants who completed the study, the mean severity of the depressive symptoms was more reduced in the treatment group than in the control group (Hamilton rating scale for depression, P = 0.002; Beck depression inventory, P = 0.006). For the sample analysed by modified intention to treat and last observation carried forward, the mean differences for the Hamilton and Beck scores between the two groups was highly significant (P = 0.007 and P = 0.012, respectively).

Conclusions The therapy was effective in alleviating symptoms of depression after two weeks of treatment. Animal facilitated therapy with dolphins is an effective treatment for mild to moderate depression, which is based on a holistic approach, through interaction with animals in nature.


  • Contributors CA participated in the design of the study, carried out the trial, and wrote the paper. MR led the design of the study, supervised the data analysis, and cowrote the paper. Both authors are joint guarantors.

  • Funding Voluntary contributions acknowledged above.

  • Competing interests None declared.

  • Ethical approval Bioethical committee of the scientific research unit of the Universidad Nacional Autonoma de Honduras, Faculty of Medical Sciences.

  • Accepted 27 June 2005
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