Chemistry of the Placebo Effect: Why Aren’t Placebo Treatments Used More?

Many will be familiar with the placebo effect: the beneficial effect produced by a treatment or drug with no therapeutic value. Despite the lack of active ingredients, placebo drugs like sugar pills can have surprisingly powerful effects, particularly in the management of pain and depression.

Placebo treatments are usually discussed in the context of clinical trials, in which they are used to ensure that the treatment being tested actually works better than the ‘fake’ treatment. Yet outside of clinical trials, placebo treatments currently have no place in modern medicine, despite the evidence that they can have real benefits for some patients.

Part of the problem lies in the lack of a proven biological mechanism. The placebo effect is typically thought of as psychological rather than chemical: the ritual of taking the treatment every day, the interaction with a doctor to receive the treatment, and the anticipation of getting better are thought to be at the root of the placebo effect. However, many doctors are reluctant to trust a medication with no proven chemical action.

Yet even if the placebo effect is psychological, this must ultimately be the result of chemical signals in the brain – to suggest otherwise is to stray from science and into spirituality. We have understood for some time that there is a link between the placebo effect and the reward neurotransmitter dopamine. Placebo treatment in Parkinson’s disease can enhance dopamine release, and higher levels of dopamine in the brain are associated with a stronger placebo response.

Our lack of understanding of the placebo effect does not make it any less real – if these treatments work, and appear to have a biological underpinning, it seems a waste not to use them in a clinical setting. However, this path is fraught with ethical problems that would need to be overcome. Doctors can hardly lie about the drugs they are giving out, and so patients would need to know that the treatment they are receiving is in fact a placebo. Evidence shows that this does not necessarily reduce the effectiveness of the treatment. However, there is also some concern that placebo treatments would put the burden on patients to make themselves better – the patient is still asked to tell themselves that the treatment will work.

If these problems are to be avoided, perhaps placebo treatments could be used to augment existing medication. Taking two pills a day might be more effective than one, even if the second pill is a sugar pill.