What’s the biggest difference between Americans and Britons? Is it the broad vowel sounds, the prevalence of guns, or the belief in God? No, it’s the number of healthy people who believe they have a medical issue.

Call it the medicalisation of life, or slick marketing, the fact is there is an entire industry in America dedicated to turning the human condition into a chronic disease.

The topic has resurfaced because the Supreme Court has been listening to arguments in King v Burwell — ostensibly a lawsuit about the legality of federal health insurance schemes, but in reality an attempt by rightwingers to kill the Affordable Care Act (ACA), known as Obamacare. A ruling is expected in June.

If Obamacare is struck down, one consequence will be a resurgence in health costs. The ACA is problematic, but its limits on Medicare payments and emphasis on lower-cost preventative medicine over higher-priced chronic-disease care has had a beneficial effect; last year’s rate of growth in healthcare spending was the slowest since 1960.

No sane person would argue that medical innovation is bad, or that the relief of suffering is not a worthy end. Who doesn’t hope scientists will be able to prevent Alzheimer’s or cure cancer. But along with the miracle of modern medicine something else has been happening, something so insidious and pervasive to the concept of wellbeing that it took a while before anybody noticed.

Sociologists first identified the mission creep in healthcare in the 1960s; but it was another decade before the philosopher Ivan Illich popularised the term “medicalisation” in his 1975 book Limits to Medicine: Medical Nemesis. In his words, “the medical establishment has become a major threat to health”. I can only imagine what he would say now when so much of medicine is no longer about health but consumption.

If the American healthcare industry were a country, it would be the sixth-largest economy in the world. Or to put it another way, at nearly $3 trillion (£2 trillion) a year, it’s more than Britain’s GDP.

At one end of the spectrum, medicalisation means not prolonging life but ensuring painful death. Every year about 30,000 people die in America from overly aggressive medicine; more are being killed by too much treatment than by too little.

As for the well and truly dying, a recent study by the Rand Corporation showed that intervention is causing more suffering to patients now than 20 years ago. The author and surgeon Atul Gawande has been fighting a one-man battle to convince his profession about the dangers of “medicalising mortality”, so far with limited effect.

Further down the scale, there’s just the sheer waste of time, energy and resources spent on unnecessary surgery — and I don’t mean facelifts. For example, every year there are roughly 650,000 arthroscopic knee operations for arthritis. Yet studies have shown the surgery has the same physical outcome as taking a placebo. Doctors perform it because of patient demand and insurance companies’ willingness to pay. Moving from surgery to pill popping, the possibilities for medical intervention rise exponentially.

Leaving aside the $12bn Americans spend on ineffective herbal cures and vitamin supplements, billions more go on treatments for illnesses that don’t exist or are very rare. One is acid reflux disease in infants. Thousands, if not millions, of parents — myself included — have treated their regurgitating babies with prescription medicines known as PPIs (proton pump inhibitors).

According to a key study by Michigan University, that makes us either clueless or trigger-happy. All babies spit up. A tiny minority have a genuine condition. Yet somewhere along the line we were convinced this entirely normal behaviour was a serious but treatable illness.

If medicalisation were only about the fantastic waste of money, the needless suffering, or the fact that we are becoming a nation of self-defeating hypochondriacs, that would be bad enough. From shyness to cellulite, there are a whole range of traits and characteristics that have been labelled, diagnosed and assigned a treatment.

It’s not just me saying this; nor are critics just betraying a puritanical reaction against people wanting to look younger or slimmer. The problem is the ever-increasing pressure towards social conformity. There is a danger normality, let alone “perfection”, may become achievable only through medical intervention, especially for women. Ten years ago, for example, labiaplasty, which alters the look of the labia, almost never happened. In 2013 it was the second-fastest-growing form of surgery in the country.

The pornification of entertainment is largely blamed for the rise — women reacting to the peddling of a non-existent ideal. But equally culpable is the healthcare industry’s uncanny ability to turn difference into a disorder. One such difference between men and women is the latter often have sex without orgasm.

Unlike erectile dysfunction, this isn’t a medical condition. There are an infinite number of reasons why a woman won’t experience one at any particular moment, from tiredness to poor sexual positioning. But that hasn’t stopped companies coming up with the label “female sexual dysfunction” and a variety of pills that are alleged to treat it.

Last month a psychiatrist writing in The New York Times accused the pharmaceutical industry of turning women into a medical problem. Being emotional, as women frequently are, wrote Julie Holland, “is a sign of health, not disease”. Yet one in four women in America is prescribed antidepressants.

Could that many women really be clinically ill; or are their tears, anxieties, rages and sorrows too messy for modern life? Isn’t it just easier for all concerned if the female of the species stays pliant?

There’s no secret as to why this is happening; the endless flow of money is the driving force behind medicalisation. Only the lack of it has the power to reverse the trend. It makes Obamacare, with its ham-fisted attempts at fiscal control, the best hope we have — at least until June.