Anorexia nervosa is a hot topic in two senses: it is a subject of high-profile discussion and it is emotionally charged. Recent remarks by Dame Joan Bakewell have fuelled the fire; the meanings of her moderate words (anorexia “could be about…narcissism really” arising from preoccupation with “being beautiful and healthy [sic!] and thin”) have sparked idiosyncratic interpretations that generate argument but evade logic.

One unexamined assumption in the ensuing furore, for example, is that anorexia nervosa is a recent epidemic spread on the wings of social media, particularly the selfie-culture. A search of online PsychINFO and Medline/Pubmed databases, however, reveals no evidence for the underlying assumption that anorexia is increasing.

An awful, disturbing expansion of the condition occurred throughout the last century, but since 1985 – before “selfie” was a word, before Facebook was a common feature of young people’s lives, before iPhones - the overall incidence has remained stable. This is not a reason to be sanguine. Anorexia nervosa affects 1 in 150 adolescents, the large majority of whom are female. It involves severe, self-inflicted weight loss and has a higher mortality rate than any other mental disorder.

The causes are complex, often interwoven with anxiety, depression and other types of self-harm

The causes are complex, often interwoven with anxiety, depression and other types of self-harm. Yet many people – layman parent, journalist, medical professional – are confident they know “the cause”. When I first began my research on teenagers, mother-blame was in fashion. An anorexic girl, it was thought, would have a mother who is unresponsive to her child’s (usually a daughter’s) own needs. Hence the girl feels ashamed of her desires and appetites; she starves herself to deny their existence.

More recently the focus has shifted from mother to media: size 0, air-brushed models have come to the fore; the advertising industry and “media culture” in general are seen to foster an ideal physique that can be met only when normal healthy development is thwarted via starvation. Distorted physical ideals affect everyone, but teenage girls seem particularly sensitive to them. A special sensitivity to pleasing others puts them at risk of all kinds of self-sacrifice.

When Joan Jacobs Blumberg looked at girls’ diaries across the past hundred years, she found a shift from “being good” to “looking good” as moral worth became equated with physical appearance. While neuroscience has entered the law courts and the education system, it remains in the margins of discussions about anorexia; but new brain imaging techniques suggest profound functional disturbance in ways someone in the grip of anorexia perceives herself; even if she manages to attain a healthy weight, blood flow to brain areas associated with self-perception remain reduced. Hence parents often describe a dizzying chasm lodged between them and the daughter whom they try reason with and reassure.

Half of the girls wanted to be three sizes smaller than they actually were; they saw the slimmest option as the best one

One reason anorexia raises such alarm in parents is that the mindset in which it develops is far more prevalent than the condition itself. Body dissatisfaction seems to kick in at an early age (and the most pronounced epidemiological change in anorexia has been the age of onset: overall the incidence has not increased but girls become susceptible to it at an increasingly younger age). A few years ago I participated in an exercise whereby three groups of girls – one aged six, one aged nine, one aged twelve, and all of normal weight – were asked to select their ideal body image from a series of digitally altered pictures at 5% increments. Half of the six year olds wanted to be three sizes smaller than they actually were; already they saw the slimmest option as the best one. But I also discovered that they eagerly engaged with attempts to resist the skinny ideal. When we all sat together, discussing who was slender and attractive, and who would be a good friend, they absorbed talk that shifted the perspective from “looking good” to “being interesting”.

Tell girls a story about a person’s feelings and goals and challenges and achievements, and their focus on the body perfect dissolves into a fascinated empathy with who a person really is. While a teen might resist such coaching (after all, the teen “knows everything and we know nothing") very young girls delight in the intimacy of wise conversations. In all the debate about a self-absorbed or narcissistic society there is little research on pragmatic prevention or critical periods of development or windows of opportunity. What I realised as I observed those six-year-old girls participating in the exercise was that we who complain about the culture of “looks” have more power than we may suppose to change the micro-culture of young people close to us.

See also Terri’s blog on the positive effects of sport