Power of placebos: Canadian psychiatrists more ready than other physicians to acknowledge the benefits of placebos, survey shows

Moreover, an even higher proportion of psychiatrists (more than 35 per cent) reported prescribing subtherapeutic doses of medication (that is, doses that are below, sometimes considerably below, the minimal recommended therapeutic level) to treat their patients.

Prescribing pseudoplacebos -- that is treatments that are active in principle, but that are unlikely to be effective for the condition being treated, e.g., using vitamins to treat chronic insomnia -- is more widespread than we may have thought according to the survey. Dr. Raz and his colleagues suggest that this may be because physicians have shown themselves to be more prepared to prescribe biochemically active materials even though at lower doses than might be effective.

The survey, which was also designed to explore attitudes toward placebo use, found that the majority of responding psychiatrists (more than 60 per cent) believe that placebos can have therapeutic effects. This is a significantly higher proportion than for other medical practitioners. "Psychiatrists seem to place more value in the influence placebos wield on the mind and body," says Raz. Only 2 per cent of those psychiatrists believe that placebos have no clinical benefit at all.

Raz's own interest in placebos grew out of his work in three very different areas: his explorations into how people's physiology is influenced by their expectations of what is about to happen, his work on deception; and the time he spent as a former magician. Together, these three separate areas of experience have led Raz to explore what remains an uncomfortable hinterland of medical practice for many practitioners -- the use of placebos in medicine.

"While most physicians probably appreciate the clinical merits of placebos, limited guidelines and scientific knowledge, as well as ethical considerations, impede open discussion about the best way we may want re-introduce placebos into the medical milieu," says Raz. He adds, "This survey provides a valuable starting point for further investigations into Canadian physicians' attitudes towards and use of placebos."

The research was funded by: the Canadian Institute of Health Research, the Natural Sciences and Engineering Research Council of Canada, and the Oxford-McGill Neuroscience Collaboration.