From the moment I was diagnosed with anorexia nervosa, I couldn’t shake one question: How did this happen?

How did my innocuous interest in health and fitness suddenly become so dangerous? Was I more predisposed to this than someone else? If so, why?

My naturally curious thought processes reminded me of a concept I’d learned in elective psychology classes: nature vs. nurture. The theory supports the idea that who we are as humans is some combination of nature (biology, genetics, DNA, etc.) and nurture (environment, upbringing, events, social and economic status, etc.).

Concerning eating disorders and mental illnesses, questions surrounding this nature vs. nurture debate might include:

Do symptoms arise because of our environmental circumstances?
Or are we hardwired from birth to develop symptoms because our family members also did?

Contrary to the early-day beliefs that eating disorders are psychosomatic diseases that can be cured just by “eating,” recent research has revealed that there is indeed a genetic link found in eating disorders.

I set out to learn more about this link. And if we know eating disorders are partly genetic, how can we encourage more open conversations about our family histories?

Genetics and eating disorders: What the research tells us

Within the last few years, decades of research have revealed a definitive genetic link for eating disorders. Through twin and family studies, we’ve learned that specific genetic markers are relationally replicated and predispose our kin to behaviors like restricting and bingeing.

More specifically, people whose family members have experienced anorexia nervosa are **11 times more likely** to develop anorexia nervosa themselves, compared to individuals who do not have this familial connection. *Source*

One study that took a closer look at this connection is the Eating Disorders Genetics Initiative (EDGI), led by Cynthia Bulik, PhD, founding director of UNC Chapel Hill’s Center of Excellence for Eating Disorders.

The EDGI—the largest-ever genetic research study of eating disorders—is known as a genome-wide association study (GWAS). These types of studies rapidly scan markers across a human’s genome to find genetic variations that might be associated with different diseases.

The EDGI wanted to identify why some people develop eating disorders—specifically anorexia nervosa, bulimia nervosa, and binge eating disorder—while others don’t.

According to Dr. Bulik:

“Many factors influence whether someone will develop an eating disorder, including genetics, thinking styles—such as perfectionism—body dissatisfaction, and societal or cultural pressures to be thin. Although environment definitely plays a role, recent research has shown that between 40 and 60 percent of the vulnerability to develop an eating disorder is due to genetic factors.” Source

What this means is that even in the face of pervasive diet culture, a fixation on thinness, and body image pressure—all of which don’t seem to be going anywhere anytime soon—it’s not necessarily guaranteed that these societal influences will single-handedly cause someone to develop an eating disorder.

Read: Eating disorders and perfectionism

How does it all work?

Without delving too much into the scientific complexities around these findings (after all, I’m not a scientist or researcher), I sought to make sense of the genetic connection in the simplest terms possible. Here’s what I managed to eke out.

You’re likely familiar with serotonin—the neurotransmitter that regulates mood, appetite, and sleep. One study from 2015 found a variant of the gene that transports serotonin. The existence of this variant influences how our brains regulate eating behavior, appetite, body image, and mood. A genetic deficiency in serotonin might increase a person’s risk of developing anorexia nervosa.

[Inserts the graphic depiction I wish I had because I’m a visual learner.]

Another study found a variant in something called Early B-Cell Factor 1 (EBF1), which plays a complicated role in regulating expressions of leptin in the body. Leptin is “the fullness hormone” that helps regulate appetite and energy. The existence of this variant suggests that these individuals may have low circulating levels of leptin, and low levels of leptin commonly occur in patients with anorexia nervosa. Source

Co-occurring disorders

What about the co-occurrence of other mental ailments? Why do so many of us who struggle with eating disorders also tend to struggle with things like depression, anxiety, obsessive-compulsive disorder, and substance abuse?

One study revealed genetic correlations between eating disorders and co-occurring diseases like those mentioned above: “Similar prefrontal cortex expression alterations mean that these disorders may have similar functional pathways.” Source

The serotonin connection mentioned above might also come into play here. A deficiency or dysregulation of this hormone can lead to all sorts of mood abnormalities and expressions.

Read: The parallels between eating disorders and addiction

What does this mean for eating disorder recovery and treatment?

Medical research studies have been instrumental in helping us figure out where diseases come from and how they behave. This knowledge also helps clinicians develop more effective treatment modalities.

For example, knowing that eating disorders have a huge genetic component requires a more strategic recovery approach than just forcing someone with anorexia nervosa to eat and gain weight.

While weight reestablishment *can* be a part of a recovery plan, individuals need a multi-pronged strategy. Through psychotherapy, for example, individuals can explore any underlying familial connections that may have predisposed them to disordered eating.

How to explore your own genetic predisposition to eating disorders

Now that we know there is a definitive connection between our genetic makeup and the likelihood of developing certain diseases, how can we address it head-on?

Conduct genetic investigations

Although there’s no genetic test we can take that can tell us whether we have these specific gene expressions (since there isn’t one single gene that can predict the eventual development of an eating disorder), we can dig through our family history in hopes of having open conversations about our mental health histories. (Scroll down to this post’s writing prompt to begin!)

Keep an eye on external stressors

Despite this post’s heavy focus on the genetic component of disordered eating, let’s not forget that major life events, bodily changes, and other factors also play a role. When we experience these tumultuous times, we have an opportunity to take stock of our behaviors and make note of any that seem abnormal, unusual, and/or potentially harmful.

Start building coping skills

If symptoms do arise, knowing how to cope with them can provide a soft landing for hard times. You can get ahead of this by building an encouraging self-talk practice or seeing a nutritionist who specializes in eating disorders. If we carried a gene that made us more likely to get cancer, we’d get screened for lumps, right? This same prevention strategy can (and should) be applied to mental illnesses like eating disorders.

Are eating disorders hereditary? The genetic link and what you can do about it