If you were asked to name the defining breakthroughs of scientific history, chances are you might consider the theorems and innovations of Galileo, Einstein, or Darwin. Jenner’s smallpox vaccine or Watson and Crick’s double helix, perhaps. Or the apple knocking some eureka into Isaac Newton. Each one a remarkable discovery, and each one deserving our highest possible esteem.

One that might have failed to make your list, though no less deserving, is the clinical trial — the elegant concept of splitting people up into groups, giving them different treatments, and seeing how they fare.

While seemingly unremarkable, clinical trials have been a cornerstone of public health research for almost three centuries. They have taught us the virtues of countless life-saving procedures, from warding off scurvy with citrus fruits, to hand washing in the delivery room. Meanwhile, they have saved us from a multitude of misguided practices. When was the last time your doctor prescribed a rigorous course of bloodletting?

In short, this simple method may just be the greatest scientific innovation you never noticed.

The first recorded clinical trial dates back as far as the Old Testament. Shortly after conquering Jerusalem, the king of Babylon brought the Judean Daniel to his court and proposed to feed him and his compatriots on rations of meat and wine. Preferring a diet of vegetables, Daniel pleaded with the king’s chief guard to reconsider:

“Submit us to this test for ten days. Give us only vegetables to eat and water to drink; then compare our looks with those of the young men who have lived on the food assigned by the king and be guided in your treatment of us by what you see.” (Daniel 1:12-13)

After ten days, Daniel’s men looked the healthier of the two groups, and their rations were changed accordingly. And with that, the first ever clinical trial was complete.
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Nowadays, standards are a little more rigorous, so much so that anyone wishing to perform clinical research must jump through a series of methodological hoops. Trials should involve large numbers of people; participants must be randomly allocated between the real treatment and a dummy drug (or placebo); and both the patients and doctors should be unaware of which treatment is being delivered.

These meticulous steps outline the bare bones of a randomized, double-blinded, placebo-controlled experiment — and any clinical trial worth its salt would proudly adhere to them. But why are such lengthy measures required? Couldn’t we save a lot of time and energy by simply giving our chosen remedy to a handful of willing participants, then seeing how they react to it?

Unfortunately, this alternative approach fails to account for a key problem facing clinical research: humans make terrible lab rats. We just won’t sit still. What’s more, we are prone to weird and unpredictable reactions to even the most moderate experimental scenarios. It is this tendency that makes all of the strict precautions of a clinical trial so crucial.

Take the bizarre and baffling phenomenon of the placebo effect. As alluded to throughout this series, pills without any active ingredient can have measurable effects on a patient. But that’s only the beginning.

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It turns out that not all placebos are created equal. The perceived invasiveness or intensity of a dummy treatment can change the magnitude of the reported effects. For many subjective symptoms like nausea, dizziness, and pain, it turns out that two sugar pills are better than one. And an intramuscular injection with salt water is even better.

Alas, every plastic rose has a plastic thorn. For all the positive power of placebo, there is a countervailing force.

The “nocebo effect” occurs when dummy interventions cause negative reactions or side effects. In one famous study, asthma sufferers were told they were inhaling an irritant that could potentially trigger an asthma attack. Unsurprisingly, many patients reported difficulty breathing, and a few had a full attack. After a time, they were offered a treatment that would supposedly combat the irritant. Inhaling this “cure” made many of the patients feel much better. The rub? Both the irritant and the treatment were nothing but nebulized salt water.

There are many more examples. It seems that women who believe that they are more susceptible to heart attacks might actually be more likely to suffer from them. Up to four times more likely, in fact. Meanwhile, a study in 2004 looked at the role of nocebo effects in patients suffering from allergic drug reactions. Across 600 participants, 27 per cent reported symptoms of an allergic reaction even though they had only been given a dummy treatment.

The existence of these fascinating phenomena highlights just how impressionable we are to the subtle forces of suggestion and expectation. When the simple act of taking a pill is enough to provoke an array of effects and side effects — regardless of whether that pill actually contains anything — determining the efficacy of a genuine medical intervention is a formidable challenge. It is in these muddy waters that the painstaking procedures of the controlled clinical trial help distinguish the good from the bad and from the ugly.

Health claims make catchy headlines, and they are often bold in their assertions. This week’s miracle cure is next week’s big scare, and there are rarely column inches left over for the grey area in between.

But scientific progress is a slow, arduous affair, and bona fide breakthroughs are few and far between. It requires time, and it requires patience — two qualities which newspaper editors seem to believe are in short supply in their readers. And to a certain extent, this is true. When you are sitting on the subway, skimming the Metro between stops, you hardly have time to critically analyze the validity of the latest health fad.

This superficial engagement with scientific news comes at a price. Wasting $30 on a Power Balance bracelet scarcely constitutes a public health crisis. But a generation of parents declining to vaccinate their children against life-threatening diseases is rather more troubling.

All that we ask is that the next time you cast your eye over a 10-word scientific revelation, it is with a healthy dose of skepticism.