An eating disorder is a pattern of abnormal food intake that reduces someone's ability to maintain adequate nutrition. Because they directly impact not only the patient's physical well-being, but also their psychological health as well, eating disorders are among the most harmful and destructive of all mental disorders. The term eating disorder is often used to refer to two conditions primarily, anorexia nervosa and bulimia nervosa.
Both anorexia and bulimia follow a similar pattern involving two things. Overvalued beliefs about weight, such as spending hours each day worrying about being fat, as well as the maladaptive behaviors that follow, such as restricting food or vomiting after eating. From there, however, the similarities between the two disorders quickly end.
In fact, while anorexia and bulimia are often lumped together, there are so many differences between the two that it's helpful to think of them as entirely separate disorders, despite the fact that they both involve eating habits. While popular conceptions generally hold that restricting equals anorexia and vomiting equals bulimia, the fact of the matter is that neither of these behaviors is diagnostic, as some cases of anorexia involve purging and some cases of bulimia involve restricting. Instead, what differs between these disorders is not the behavior itself but rather the thought process underlying those behaviors, as we'll go over in this video lecture. Before we move on, we'll be referencing past videos quite a bit in this lecture.
So if you haven't seen the lectures on OCD and personality disorders, and obsessive-compulsive and borderline personality disorders in particular, make sure to watch those first. I'll put links in the description below. Okay, let's talk about these two disorders in more detail, starting with anorexia.
The core patterns of this disorder can easily be memorized by thinking of it as under-rexia. Let's build out each part of this mnemonic letter by letter. First, at its core, anorexia is a disorder in which people perceive themselves to be overweight even though they are severely underweight by any objective standard. The fact that patients with anorexia have a below average weight for their age and height is a required part of the diagnosis and helps to distinguish it from other eating disorders.
The patient's body mass index or BMI is often used as a way of quantifying how underweight someone is with the BMI of less than 17.5 being the cutoff. This low weight is accompanied by a cognitive pattern of profound nervousness about gaining weight. When talking to someone with anorexia, it soon becomes clear just how preoccupied they are by the fear of gaining weight, and many patients will spend hours each day thinking about their weight and trying to come up with ways to lose weight.
However, no amount of weight loss will convince the patient that they're thin. This is because anorexia is a disorder of distorted perceptions with the problem lying not in the body but in the mind. This is the key to understanding anorexia and is what differentiates it from normal attempts to lose weight.
Whereas most people who engage in diet and exercise to lose weight will be satisfied when they're able to shed a few pounds, for someone with anorexia there's no end to the feeling that they're overweight, leading to ongoing attempts to lose weight even when they are below a healthy weight. These attempts to lose weight come in two main forms. First is trying to burn off any calories that have been ingested. Excessive exercise is the most common method although other strategies like vomiting or abusing laxatives can be used as well.
Second is restricting calories, either by narrowing food intake to include only certain healthy or low-calorie foods like celery or carrots, or by trying to avoid eating altogether. In severe cases, patients will have not eaten for weeks or even months at a time. Complete elimination of food intake can lead to a state of severe malnutrition which negatively impacts every organ system in the body.
People with anorexia often develop various medical problems including fatigue, amenorrhea, infertility, osteoporosis, electrolyte abnormalities, and cardiac arrhythmias, and it is not uncommon for someone with severe anorexia to end up in the hospital due to medical complications from malnutrition. Even when hospitalized, however, people with anorexia will continue to see themselves as overweight and will persist in refusing food, leading to a state of total starvation in which damage to essential organ systems begins to occur. The ability of patients with anorexia to believe that they're overweight, despite all evidence of the contrary, highlights once again how distorted self-perception is the foundation upon which anorexia rests, as, without it, the disorder would not become an endless cycle. The idea of an endless cycle may make you think of obsessive-compulsive disorder, and indeed, anorexia seems to make a lot of sense when viewed through the lens of OCD.
Both disorders involve obsessive thoughts, about weight in the case of anorexia, that lead to specific compulsive behaviors such as food restriction and excessive exercise, intended to help calm these thoughts. Just like an OCD, however, no amount of weight loss ever leads to that feeling of knowing that one is finally thin enough. Neurobiological studies further support the link between these two disorders, as anorexia and OCD are both associated with abnormalities in similar parts of the brain.
Despite these links, however, anorexia differs from OCD in a few key ways. Most notably, the obsession with weight in anorexia is distinctly egosyntonic rather than egodistonic, as the patient does not view their fixation on weight as being excessive or dysfunctional in any From this perspective, anorexia may actually be closer to obsessive-compulsive personality disorder than OCD itself, which is reflected in higher rates of comorbidity with OCPD than with textbook OCD. Anorexia also shares with OCPD a characteristic rigidity of behavior, such as eating the same thing at the same time every day with little variation, and a high degree of conscientiousness that plays directly into the distorted beliefs at the heart of the condition, such as believing that it is wrong to be fat. Overall, using what you've already learned about both OCD and OCPD will help you to better understand patients with anorexia.
Anorexia is a relatively rare condition that is found in less than 0.5% of the population. It often begins around the time of puberty and young adulthood, with a median age of onset of 18 years. Women are affected about 10 times as often as men.
Social circumstances that can produce extreme pressure to be thin, such as participating in modeling or dancing. are associated with higher rates of anorexia, suggesting that environmental and social factors play a large role in this disorder. The prognosis for anorexia is variable, with some people only engaging in transient episodes of food restriction while others avoid food entirely for weeks or months at a time. Because of the medical complications as well as a moderate risk of suicide, anorexia is the single most deadly mental illness, with up to 20% of people with this disorder dying as a result. with 5% dying within a decade of the initial diagnosis.
Treatment of anorexia involves nutritional rehabilitation, monitoring for medical complications of malnutrition, and engaging in psychotherapy. For adolescents and young adults, therapy that involves the entire family structure, rather than just the patient themselves, has been shown to be the most effective option. Medications play a very limited role in treatment of anorexia, as none have been shown to improve any clinically significant outcomes.
Even with full effort on the part of the clinician, however, anorexia is a very difficult disorder to treat, as the egocentronic nature of the condition frequently makes patients reluctant to engage in treatment. Nevertheless, these patients deserve our best and most persistent efforts. So now that we have an understanding of anorexia, let's turn our attention to bulimia.
Just like we renamed anorexia as under-rexia to remember the key patterns associated with it, let's think of bulimia nervosa as bul-emia. This will help you remember that bulimia involves episodes of impulsive binge eating where the patient consumes large amounts of food in a short amount of time. Binge eating isn't just having an extra cookie or bowl of ice cream after a meal.
Instead, people who are binging eat enormous amounts of food, like several containers of ice cream along with a whole batch of cookies, a few bags of chips, and an entire pizza. Some patients will go to the store to buy a week's worth of food and end up eating it all before the day is over. Patients often report feelings of having very little control over their eating right before an episode, then emotional numbness during an episode, and finally shame, disgust, and guilt immediately after an episode. Because of this sudden onset of remorse, patients will follow up these binges by engaging in purging or offsetting behaviors intended to prevent the food that has just been binged from being absorbed into the body as calories. Self-induced vomiting is the most common form of purging and is the one most associated with bulimia.
though people with bulimia will sometimes engage in other offsetting behaviors such as abuse of laxatives as well. Purging through vomiting is often effective at preventing weight gain, but it can lead to its own host of complications including physical injury to the mouth, teeth, and esophagus, kidney damage from dehydration, electrolyte abnormalities such as metabolic alkalosis related to loss of stomach acid, changes in key hormone levels, and gastric ulcers. Frequent vomiting can also damage the esophagus which can then rupture. which is known as Boerhaave syndrome. On physical exam, you may see signs of recurrent vomiting, including erosion of dental enamel, swollen salivary glands, and injuries on the back of the knuckles from scraping against the teeth during self-induced vomiting.
Continuing on in our bulimia mnemonic, the W stands for weekly, as binging and purging episodes must have happened at least once a week for a period of three months to meet DSM criteria for the disorder. Finally, the L stands for linked to self-esteem. Like anorexia, the disordered eating behaviors seen in bulimia are accompanied by distress about feeling overweight.
Unlike anorexia, however, which is more linked to distorted perceptions of weight, someone with bulimia has instead linked their concerns about weight to poor self-esteem, extreme interpersonal rejection sensitivity, and fear of being alone, such as believing that, if I'm fat, then other people will not like me and I'll have no friends. On a mechanistic level, the mention of poor self-image interpersonal rejection sensitivity, and fear of being alone should immediately remind you of borderline personality disorder and other cluster B disorders. Indeed, the comorbidity between these two disorders is incredibly high, with over 50% of people with bulimia meeting criteria for BPD as well.
In fact, people with bulimia share so many other features with BPD, including chronic dysphoria and a high degree of impulsivity, that it seems reasonable to suggest that, in many cases, bulimia can best be understood as an eating-based manifestation of the maladaptive pattern seen in BPD. If we focus on the B of both bulimia and borderline personality disorder, You can more easily remember the link between these two conditions. The prevalence of bulimia in the general population is around 1%, making it about twice as common as anorexia, though still relatively rare overall.
The age of onset is roughly the same, with the patterns of bulimia beginning in adolescence or early adulthood. Also like anorexia, bulimia is diagnosed more than 10 times as often in women compared to men. However, in contrast to anorexia, where someone must be underweight to be diagnosed, In bulimia, most people have a normal weight or are even slightly overweight.
Bulimia has a variable prognosis, with some people being able to stop binging and purging on their own, while others require intensive treatment. Ten years after the initial diagnosis, about half of people with bulimia will have recovered fully, one-third will have made a partial recovery, and 10-20% will still have disordered eating habits. While recurrent vomiting can lead to various medical problems as outlined earlier, As a general rule, the medical complications associated with bulimia are not as severe as those seen in anorexia, and the mortality rate is significantly lower.
Effective treatment for bulimia does exist, as both medications and therapy appear to be effective, with a combination of the two being superior to either alone. In particular, CBT and a form of psychotherapy known as interpersonal therapy are both associated with improvements in symptoms, with a moderate effect size. SSRIs and other serotonin-boosting medications are also helpful with a small effect size.
Importantly, a specific antidepressant known as bupropion must absolutely be avoided for patients with bulimia who are actively vomiting as its use may increase the risk of seizures. This is a high yield point that you should make sure to remember as we finish up our discussion of bulimia. While anorexia and bulimia are the two most widely known eating disorders, there are two other patterns of disordered eating that are now recognized in the DSM as well. We'll talk first about binge eating disorder. This is listed as a separate diagnosis in the DSM, but in practice it is similar in nearly every way to bulimia except that the binging episodes are not followed by offsetting purging behavior.
Due to this lack of purging, people with binge eating disorder are often quite overweight as compared to underweight in anorexia and normal weight in bulimia. In addition, binge eating disorder is equally prevalent in men and women suggesting that purging as a specific offsetting behavior likely has a large learned or social component. Binge eating disorder also has a better prognosis compared to bulimia, with 80% of people being in remission at 5 years.
Aside from these specific differences, however, the overall pattern of binge eating disorder is very similar to bulimia, including a strong association with borderline personality disorder and a good response to both psychotherapy and antidepressants. With all of this in mind, it's perhaps best to conceptualize binge eating disorder as a less severe variant of bulimia without the compensatory offsetting behaviors. Finally, we will talk about avoidant restrictive food intake disorder, or ARFID. ARFID is a relatively new diagnosis, as it was only recently introduced in the DSM-5, so we don't know as much about it as we do about anorexia or bulimia. However, let's see if we can make some sense of it based on what we have already learned.
Similar to anorexia, people with ARFID tend to avoid food or will eat only a very narrow selection of foods, resulting in a failure to eat enough to stay healthy. Unlike anorexia, however, food avoidance in ARFID is not linked to fear of gaining weight. Instead, people with ARFID avoid food due to various other reasons, including a chronically low appetite or having strong reactions to characteristics of certain food items such as their color, appearance, texture, or smell.
For some patients, ARFID can also develop due to anxiety about the consequences of eating, but unlike in anorexia, the feared outcome is not weight gain, but rather some other aversive food-related experience such as choking, vomiting, or constipation. In these cases, there is often a history of such an event happening, after which the food avoidance began. More than just being picky eaters, people with ARFID avoid food to the extent that they lose a significant amount of weight, sometimes to a similar level as seen in anorexia.
have major nutritional deficiencies, or even will require a feeding tube or other forms of supplemental nutrition to stay healthy. Studies on the prevalence of ARFID are limited, but the data that exist suggests that it is a rare condition, affecting only around 0.2% of the population. ARFID tends to begin during childhood, with many patients first showing patterns of the disorder around the age of 5 or 6. However, some patients continue to have food avoidance into adulthood as well. CBT is a treatment of choice for ARFID, with a particular focus on managing anxious thoughts about specific types of food, as well as rewarding exposures to new foods.
So those are the main eating disorder diagnoses to be aware of. For many people, eating and its associated rituals such as having dinner with family, making a meal with friends, or experiencing a new type of food while traveling are among the most delightful moments of life. If all eating disorders did was rob these moments of their joy, that would be bad enough.
However, because eating disorders threaten not just the quality of life, but even life itself by leading to malnutrition, medical complications, and, in severe cases of anorexia, even complete starvation, it's essential to be on the lookout for these conditions and know how to both diagnose and treat them in our patients. Thanks for watching this video. More than most topics we've covered Eden disorders rely upon an understanding of other diagnoses in psychiatry. If you want to put your differential diagnosis skills to the test, pick up my book Memorable Psychiatry on Amazon which has over 100 practice questions to sharpen your knowledge.
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