A survey of UK doctors found that nearly all admitted prescribing treatments they knew would have no direct pharmacological effect, including antibiotics for viral infections.
The survey findings present strong practice-level evidence that placebos have a real health impact – which has implications for the debate around whether homeopathic medicines should be used in the NHS.
The study authors emphasised that the ‘placebo effect’ is not medically negligible: a placebo treatment can help to stimulate neurological and endocrine reactions to the disease, reducing the symptoms.
‘Impure placebos’ are real treatments whose efficacy for that particular patient is doubtful. It differs from off-label use, where the drug is not approved for that indication but there is trust in its efficacy.
In addition, 12% of GPs admitted prescribing ‘pure placebos’ (with no active ingredient) to reassure patients whose anxiety was itself a health risk factor.
Researchers at the Universities of Oxford and Southampton analysed the responses of 783 GPs to an online survey. The respondent population was analysed and judged representative of registered GPs in general.
The survey found that doctors used impure placebos to induce psychological treatment effects, to counter patient anxiety or to comply with patient choice.
While 84% of doctors judged the use of impure placebos to be acceptable in some situations (and 66% supported the use of pure placebos), more than 80% said their use should not involve deception.
Professor George Lewith, co-lead author of the University of Southampton study, said the two studies showed that “doctors are generally using placebos in good faith to help patients”.
Previous studies “have clearly shown placebos can help many people and can be effective for a long time after administration,” he added. “The placebo effect works by releasing our body’s own natural painkillers into our nervous system.
“In my opinion the stigma attached to placebo use is irrational, and further investigation is needed to develop ethical, cost-effective placebos.”
The use of placebos is discouraged by the General Medical Council. However, Dr Jeremy Howick, co-lead author of the University of Oxford study, argued: “Current ethical rulings on placebos ought to be revisited in light of the strong evidence suggesting that doctors broadly support their use.”