Even the greatest skeptics among us accept that there is a placebo effect. Placebo-controlled trials are standard practice for testing the effectiveness of new medications. Recently, research has taken a new and interesting turn, and there have been some remarkable findings.
What is a placebo?
Placebos are ‘fake’ treatments which can take the form of pills (such as sugar pills), injections, or pretend operations or procedures. In placebo-controlled studies, fake treatments are compared with the real treatments to determine the effectiveness of the real treatments.
Time and time again, people given a placebo improve – and sometimes dramatically. However, the improvements cannot possibly be attributed to the placebo itself, so what’s going on?
The placebo effect
The placebo effect can be defined as ‘a favourable outcome arising purely from the belief that one has received a beneficial treatment’. The definition is sometimes extended to ‘a therapy without specific activity for the condition being treated, that is deliberately used for psychological or psychophysiological effect’.
The placebo effect has been shown to cause real and measurable physiological change. Despite containing nothing that will improve health, studies have had some compelling results. Placebos have been shown to treat pain and depression and even alleviate symptoms and improve function in Parkinson’s disease and osteoarthritis. Placebos don’t work for everything: they can’t alter blood sugar levels in diabetes, mend a broken leg or cure cancer. However, they can work for conditions that are defined by ‘self-observation’ symptoms such as pain, nausea or fatigue.
What causes the placebo effect?
Our expectations have a powerful influence on the physiologic response of our bodies. At the core of the placebo effect is the mind–body interaction. People’s beliefs, expectations, and desire for improvement all combine to change the chemicals in the body. Our brains are capable of producing countless chemicals that reduce pain, energise us, or help us sleep. The placebo effect taps into our natural pharmacy, however, the specific physiological responses that elicit the effect are still not well understood.
Our response to stressful situations demonstrates the power of the mind on chemical changes in our bodies. When we perceive that a situation is stressful, hormones such as adrenaline and norepinephrine are released into the bloodstream causing our heart to beat faster and our blood pressure to rise. Commonly known as the ‘fight-or-flight’ response, this is an example of a physiological reaction resulting from our thought processes and perception of a situation.
Placebos and health
The chemicals that mediate the placebo effect appear to differ according to the health condition. For example, dopamine has been attributed to the placebo effect in Parkinson’s disease, opioids in pain disorders, and serotonin in depression.
A significant proportion of research has occurred in the fields of pain and pain relief (analgesia). The placebo effect triggers distinct brain areas associated with anxiety and pain that can activate physiological effects that lead to healing. Changes in brain chemistry and brain activity occur in anticipation of the analgesia provided by placebos. Certain neurotransmitters in the brain are released which can reduce pain and enable people to move more comfortably. Brain scans during studies show that endogenous opoids are released in the brain – the brain’s natural morphine – which has the same effect as opiate drugs, such as morphine. A dummy pill can release the naturally occurring pain killers in our brains, entirely because of our belief in its ability to provide benefit.
Clinical trials of antidepressants have repeatedly shown that leading brands of antidepressants work little better than placebos. That is, placebos provide almost as much benefit in reducing depression as antidepressant medication, with the difference being small and not clinically significant. This presents a therapeutic dilemma. The effect of antidepressants is not clinically significant, but the placebo effect is.
Even when people know they are receiving a placebo, their symptoms improve
New research shows that the placebo effect works, even when people know they are getting a fake treatment. In a study looked investigating irritable bowel syndrome (IBS), half the volunteers were told they were getting an ‘open-label’ placebo and the others got nothing at all. There was a dramatic and significant reduction in the placebo group’s IBS symptoms (cramping, diarrhoea or constipation), even though they were explicitly told they were getting a ‘sugar pill’ without any active medication. Several study participants wanted more placebo pills at the conclusion of the trial. Other ‘open-label’ placebo studies into cancer-related fatigue and chronic low back pain have also shown significant improvements in symptoms. If placebos are almost as effective as some treatments, but elicit no side effects, maybe placebos could be prescribed?
When an individual receives any treatment (whether it is an active treatment or not) there may be a beneficial effect resulting simply from the expectation of benefit. Placebo effects can result simply from contact with doctors or other health care providers, even in the mere act of interviewing or examining a patient in the context of a caring, therapeutic relationship.
Maybe we can harness the placebo phenomena to positively impact our own health
The fact that we can change our body’s chemical response through our thoughts, our beliefs and our expectations could have far-reaching effects on our health.
More on that in Harnessing the Placebo Effect: Part II