At the Columbia Center for Eating Disorders, we have spent the last decade-plus working to better understand the role that habits play in the persistence of anorexia nervosa. Habits are learned routines that eventually occur frequently and automatically, even though an individual’s goals may have changed In research studies using imaging methods and computer tasks, we have verified that there are neurobiological explanations for the challenges people face in trying to maintain health. For example, we now have evidence from two separate studies (found here and here) that people with anorexia nervosa are using different parts of the brain when they decide what to eat – parts of the brain that serve more habitual behavior.
Perhaps unsurprisingly, another useful way to learn about people’s habits is simply to ask. In our habit studies, we use a questionnaire called the Self-Report Habit Index to assess habit strength (or, how likely a routine is to occur, regardless of intentions).
The Self-Report Habit Index has been used to study habit strength in all kinds of health-related behaviors from cigarette smoking to teeth brushing to exercising and it reliably shows that when habits are stronger, behaviors are more persistent. The Self-Report Habit Index was especially interesting to us because its format allows respondents to generate a personalized example of a habit or routine to be used for the ratings.
We set out to better understand how habit strength in eating-related domains differed between people with and without anorexia nervosa, and to examine whether habit strength in patients had any relationship to the duration or severity of their illness.
Study Methods
In this study, 116 females – 69 with anorexia nervosa and 47 healthy controls with no eating disorder – completed the Self-Report Habit Index and a commonly used questionnaire to assess eating disorder symptoms. Study participants also joined us in our eating laboratory for a standardized meal.
Results
All individuals were able to generate examples of habits in the four eating-related domains assessed. As evident in the examples below, sometimes the examples of types of routines overlapped between groups but often they did not.
Compared to those without an eating disorder, people with anorexia nervosa reported stronger habits/routines overall and within each domain. For patients, greater habit strength was associated with greater eating disorder symptom severity and longer duration of illness.
What does it all mean?
As we’ve written previously, eating behavior exists on a spectrum ranging from normal to disordered eating to eating disordered. That all participants could relate to the idea – and generate examples – of eating-related habits provides further evidence of this. However, the strength of routines is greater for people with anorexia nervosa (and as described above, appears to be guided by different circuitry in the brain) than those without an eating disorder. (For more on the force of habit, give this podcast a listen.)
The association between habit strength and duration of illness makes sense in terms of the habit model, which would suggest that routines become more entrenched over time. However, it is also possible that a high level of habit strength is established early on or prior to the onset of anorexia nervosa and then contributes to severity and duration. While we could not test this hypothesis in the current study, we plan to investigate it further in some of our ongoing studies with patients with a recent onset of illness.
The ultimate goal of our mechanism-based science is to improve clinical treatment for eating disorders. Behavior that is governed by habit may require different interventions to affect lasting change. We have found that by focusing on these habit-like behaviors, we can help people develop new, more health-sustaining routines. Currently, we are evaluating whether a habit-based, behavioral psychotherapy, REACH+, can help prevent relapse in the 6 months following inpatient treatment, a critical period when patients are returning home to environments rich with cues (or triggers) for routines of illness.
To read more about the study described above, check out:
Davis L, Walsh BT, Schebendach J, Glasofer DR, Steinglass JE. Habits are stronger with longer duration of illness and greater severity in anorexia nervosa. Int J Eat Disord. 2020 May;53(5):413-419. doi: 10.1002/eat.23265. Epub 2020 Mar 30. PMID: 32227516; PMCID: PMC7217727.
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