I had a splitting headache to keep me company over the weekend. Not a pill popper by nature, I decided to let it wane by itself. When it showed no signs of subsiding, I finally swallowed a painkiller. Within five minutes I promptly declared that I felt finally relieved. Now, for this drug to act on my body and take care of the pain, it would have taken a minimum of 20 minutes. So what was the miracle that produced a healing effect in five minutes flat? This could be called the placebo effect.
What is placebo?
You might wonder what exactly a placebo is. It is actually nothing. An inert substance that has no inherent pharmacological activity - it resembles the comparable active drug in matter of looks, smell and taste. It's a miracle that something so chemically inert and having no molecular properties of a drug can actually heal. Due to its inert nature, it does not cause reaction in the body, but triggers the body's own natural response which could be called the healing power of nature. A placebo can cause a positive or a negative clinical effect on the patient.
How does a placebo work?
There are several theories that explain how a placebo might work. One of them is the "Natural Remission Theory" which states that the benefit brought about by the placebo is a natural progression which would have occurred even without it. Many of the placebo experiments did not have a no-treatment control group. Patients who were given medicine were compared with patients who were given an inert material. But there was no comparison with a group of similar patients that was not given any treatment.
So the chance that the patients would have recovered even without the placebo cannot be ruled out by such experiments. While this could hold true for acute conditions like a headache or a cold, it cannot completely explain the benefit in chronic conditions like long standing depression or high blood pressure. Another theory suggests that it could be a conditioning response, where the patient connects the act of taking a medicine to obtaining relief by prior conditioning. In a study done in 1998, it was proven that the body's own feel-good chemicals called endorphins had a major role to play in placebo-induced pain relief.
A person's faith in the treatment along with their suggestibility may have considerable bio-chemical effect in the body, affecting the person's neurochemistry. The body's hormonal and immune systems work on the neurochemistry and vice versa. Thus, a person's positive attitude and faith can actually aid recovery by activating the immune and hormonal systems in the body which proves that the placebo effect is not all psychological and the problem is not 'all in the mind'.
In fact, the placebo effect is a powerful part of all medical care, conventional or complementary, though its role is often undermined or misunderstood.
Proof that placebo works
The Scientific American magazine published a study performed by Tor Wagner, of the University of Michigan, and his colleagues. Functional magnetic resonance imaging [f MRI] was used to study the brains of volunteers who were exposed to harmless but painful stimuli such as small electric shocks or heat. In some cases, the researchers told participants that a pain-relieving cream had been applied to their skin.
When these subjects were shocked, they reported less pain on average than did participants lacking the "anti-pain" cream. Subjects under the influence of the placebo effect also exhibited increased brain activity in an area known as the prefrontal cortex, and decreased activity in well-known pain-sensing regions such as the thalamus, the somatosensory cortex and parts of the cerebral cortex. The results support the hypothesis that the placebo effect does not interfere with the body's ability to sense pain but instead affects how the brain modulates its interpretation of the body's signals. Paradoxically, the placebo findings could aid the development of novel therapeutic treatments for pain.
Some studies report actual physiological changes that result from placebo treatments. According to a NY Times report, doctors in one study successfully eliminated warts by painting them with a brightly coloured, inert dye and promising patients the warts would be gone when the colour wore off. In a study of asthmatics, researchers found that they could produce dilation of the airways by simply telling people they were inhaling a bronchodilator, even when they weren't. Patients suffering pain after wisdom-tooth extraction got just as much relief from a fake application of ultrasound as from a real one, so long as both patient and therapist thought the machine was on.
So whatever be the mechanisms, placebos do seem to work.
Few observations about placebo
In 1955, researcher H.K. Beecher concluded that one-third of all patients responded to a placebo. This concept is the basis for the development of placebo-controlled trials, whereby a new drug subjected to a clinical trial has to prove its superiority over a placebo and only then can it be considered to have a significant benefit.
- When a placebo is administered to replace a previously administered drug, it may also incur the same side effects as the prior actual drug.
- A placebo may not work on some disease conditions.
- A placebo that involves ingestion, injection, or incision is often more powerful than a non-invasive technique of administration.
- Placebos administered by authority icons such as doctors or spiritual leaders seem to be more powerful.
Nocebo: Placebo's evil twin
A nocebo effect makes patients feel worse [or cause other harm] for reasons unrelated to the properties of inert material prescribed to them, similar to a placebo. Drowsiness, headache, minor dizziness, difficulty in concentrating, and upset stomach are examples of effects that a nocebo can create.
A number of studies have documented the nocebo effect. E.g. volunteers were told that a mild electrical current would be passed through their heads and might cause a headache. No electrical current was actually passed, but two-thirds of them developed a headache.
- Team CW
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