This genetic breakthrough on anorexia should transform how the disease is seen

Once upon a time, disease was thought to have been sent by God as a punishment for sin.

If not, then it must surely be the work of demons, witches or groups regarded as social outcasts. Thankfully medicine has moved on from the days when Jews were blamed for outbreaks of the plague across medieval Europe, yet with psychiatric illnesses something of the old accusatory myths seem to linger. Until relatively recently, autism was still wrongly blamed on so-called “refrigerator mothers”, who supposedly damaged their children by being cold and unloving. The discovery that autism has a genetic component turned our understanding of the role it plays in families upside down, and now something similar may be happening with anorexia.

New research on DNA samples from thousands of anorexics has found a link to genes involved in regulating metabolism, as well as those connected with anxiety and obsessive compulsive disorders. The deadly compulsion to starve yourself, to put it crudely, is not all in the mind but also has something to do with the way the body processes food. That may not necessarily come as an enormous surprise to doctors – it’s not the first time research has linked eating disorders to a broken metabolism – but it’s potentially a breakthrough in how broader society views those who suffer from it, and perhaps how they see themselves.

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For years, recovering anorexics have argued that it’s dangerously simplistic to blame their illness on looking at pictures of stick-thin models in fashion magazines, or on over-anxious parents driving perfectionist children to succeed. Now the evidence is starting to back them up. The researchers involved in this study argue that while the families of anorexics do tend towards perfectionism, the cause and effect relationship might not necessarily work the way we think it does: it might be that the genetically influenced anxious mindset linked to anorexia makes people push themselves too hard.

Just because a disease has a genetic component doesn’t mean that the environment in which the sufferer is steeped is suddenly irrelevant, and in this case the researchers estimate genetics explains only about half of anorexia. It’s a piece of the jigsaw, not the whole of it. But the greater our understanding of the complicated interaction between genes and environment, the more likely we are to find that conditions once blamed on human weakness – the idea that sickness must be someone’s fault, or that they could get well if only they chose to snap out of it – have much more complicated pathologies.

What starts with anorexia doesn’t necessarily stop there. What about other eating disorders that tend to run in families, such as bulimia, or less compulsive and more common forms of overeating? Are there biological reasons why some people find it relatively easy to eat a sensible, balanced diet and others fight a lifelong losing battle with temptation?

Studies exploring these questions tend to face an irritable popular backlash, because for healthy people, the idea of blaming the sick (or, for that matter, the poor) for their own misfortune is in some ways a comforting one. It’s more soothing to think of disaster as avoidable, controllable, something that needn’t happen to people who make the “right” choices in life. But the more we unravel of our genetic inheritances, the less true that seems.

This study of what drives anorexia will have real, practical benefits in tackling a disease that’s often frighteningly resistant to treatment and prone to relapses. But like all the best science, it also has a useful lesson to teach the rest of us.

• Gaby Hinsliff is a Guardian columnist