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Case Study: What is the diagnosis?

August 25, 2025

Test your diagnostic skills with this fictional case study. We’ll review the details of the case of Leo before you determine what you think the diagnosis will be. At the end, you’ll learn the diagnosis for Leo.

The Fictional Case of Leo Sterling

Leo Sterling, a 24-year-old male, was referred to therapy by his primary care physician. The concerns noted in the referral were that Leo continues to lose weight that he does not plan or intend to lose, and notes concerns about nutritional deficiencies that are the result of Leo’s eating habits.

When you meet with Leo, he describes himself as a “creature of habit” with food. He says that he tends to stick to a narrow range of meals that he finds enjoyable. When asked if he tries new foods, he states that he just struggles to incorporate variety into his diet. He reports that certain foods “don’t sit well” with him. He expands on this saying that he finds he doesn’t care for the taste or texture of many foods. But, he also admits that there are times where he won’t eat a food because he thinks it might cause discomfort him in some way.

Leo only has a short list of foods that he eats and he prepares at home. These include things like chicken nuggets, potato chips, and apple sauce. Leo notes that he is very specific about the brand of foods that he buys and will only eat the foods if they are the specific brands he likes. He says that he has a hard time eating in unfamiliar settings, even if it is a food that he typically will eat.

As Leo has struggled with his eating, he says that he isolates more. He avoids eating in social situations, and won’t participate in group meals, even with people he knows well. Leo reports feeling quite depressed because of how disconnected he has become from people who are important to him.

When you ask Leo about his eating habits in childhood, he says that his preferences for food have been fairly consistent throughout life. However, in adolescence his preferences started to become more rigid and noticeable. Although he doesn’t remember his age at the time, Leo notes some specific memories that he has from when he was younger where he would gag on foods or feel nauseous after trying a food. But, he does not remember anything specific causing this. When Leo has tried to expand his list of go-to foods, he reports that this has been unsuccessful. He states that trying new foods is just too “stressful” for him.

In the last six months, Leo has lost 10 pounds. He isn’t sure what has led to the weight loss. However, throughout the session he mentions that he will often skip meals to avoid the stress of eating, or because he cannot find something that he will feel like eating.

Leo reports that his energy is low. He finds himself to be anxious about his vitamin levels being low and how his lab work also showed mineral deficiencies. He says that he feels defeated because “it shouldn’t be this hard to just eat normally”. Leo denies that he restricts food for the purpose of weight loss or concerns about his body image.

At his session, Leo presents as thin but neatly groomed. He maintains good eye contact with you, and his affect is congruent with his expressed anxiety, depressed mood, and frustration regarding his eating. His thought process is logical and coherent. He denies any delusional beliefs about food or body shape. He appears cooperative but seems genuinely perplexed by why he cannot simply “eat like a normal person.” You do not observe any clear signs of a thought disorder or psychotic symptoms.

Case Review

Now that you’ve reviewed the case of Leo, you can go back and re-read any parts that you need repeated. When you’re ready, continue scrolling to learn the diagnosis for Leo.

The Diagnosis

In this case, Leo is frustrated by why he “can’t eat like a normal person”. He has long-standing limitations with food, being very particular about the foods he eats, and in some cases, the brands of those foods. He also finds the tastes and textures of some foods bothersome. His eating habits are now resulting in a low body weight, vitamin and mineral deficiencies, and interference with his social life. 

For the case of Leo, he meets criteria for Avoidant/Restrictive Food Intake Disorder, or ARFID.

Review your Diagnostic and Statistical Manual of Mental Disorders (fifth edition, text revision) to learn more about this diagnosis. If you want to learn more about ARFID, make sure you subscribe as we’ll be diving into this diagnosis in the next video.

This case presentation is for entertainment and educational purposes. Any resemblance that this case has to a real situation is purely coincidence. 

References

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