Clinical Vignette
Patient: "Mr. J," 17-year-old high school junior, referred by his pediatrician for significant weight loss (15 lbs over 4 months, now at BMI 16.8). His mother is concerned he "barely eats anything."
Chief Complaint: "I just don't like most foods. The textures make me gag. I'm not trying to lose weight."
History of Present Illness: Mr. J has had a restricted diet since early childhood. His mother reports he has always been a "picky eater" but the restriction has intensified over the past year. He currently eats approximately 6 foods: plain white rice, chicken nuggets (one specific brand), plain pasta, apple slices, crackers, and milk. He refuses all vegetables, fruits (except apples), mixed-texture foods (e.g., soups, casseroles), and foods with strong odors. He describes specific sensory aversions: "mushy things make me gag," "sauces feel disgusting in my mouth," and "I can't eat anything where I can see different things mixed together." He has refused to eat at restaurants since age 12 because "they might put something on the food I don't expect." His restriction has worsened since starting a new school year, which he attributes to increased stress: "when I'm stressed, even my safe foods feel harder to eat." He denies: desire to lose weight, fear of gaining weight, body image disturbance, calorie counting, compensatory behaviors (purging, excessive exercise, laxatives), or perceiving himself as overweight. When asked about his weight loss, he states: "I know I'm skinny. I'd eat more if I could. I just can't."
Medical Workup: Mild iron deficiency anemia (Hgb 11.2). Low vitamin D. No thyroid abnormality. No GI pathology identified on basic workup.
Developmental History: Diagnosed with ADHD at age 9. Meets screening criteria for sensory processing difficulties (sensitive to clothing tags, loud noises, bright lights). No ASD diagnosis, though sensory profile is notable.
Mental Status Exam: Cooperative, slightly anxious when discussing food. Affect appropriate. No body checking behaviors observed. No distorted body image statements. Normal thought process. No suicidal ideation.
Step 1: The Diagnostic Question
Both Anorexia Nervosa and ARFID produce food restriction and weight loss. The single most important differentiating variable is the motivation for restriction:
| Feature | Anorexia Nervosa | ARFID | This Patient |
|---|---|---|---|
| Motivation for restriction | Fear of weight gain; distorted body image | Sensory aversions, fear of choking/vomiting, or lack of interest in eating | ARFID: sensory aversions ("textures make me gag") |
| Body image | Distorted: perceives self as overweight despite underweight | Intact: recognizes underweight, wants to eat more | ARFID: "I know I'm skinny. I'd eat more if I could" |
| Food selection | Based on caloric content, macros, "safe" vs "forbidden" foods | Based on sensory properties, familiarity, texture, brand | ARFID: one specific brand of nuggets; rejects mixed textures |
| Age of onset | Typically adolescence; restriction is a change from previous eating | Often childhood; longstanding pattern of selective eating | ARFID: "picky eater" since early childhood |
| Compensatory behaviors | May include purging, excessive exercise, laxatives | Absent | ARFID: none reported |
| Response to weight loss | Denial of severity; resistance to weight restoration | Recognition of problem; willing to gain weight if able | ARFID: acknowledges he is too thin, wants to eat more |
Step 2: ARFID DSM-5-TR Criteria
Criterion A: Eating or feeding disturbance manifested by persistent failure to meet nutritional/energy needs, associated with ≥1 of: (1) significant weight loss, (2) nutritional deficiency, (3) dependence on enteral feeding or supplements, (4) marked interference with psychosocial functioning.
(1) Significant weight loss: 15 lbs over 4 months, BMI 16.8. MET.
(2) Nutritional deficiency: iron deficiency anemia, low vitamin D. MET.
(4) Psychosocial interference: refuses to eat at restaurants since age 12; food restriction limits social participation. MET.
Criterion B: The disturbance is not better explained by lack of available food or an associated culturally sanctioned practice.
Food is available. No cultural restriction. MET.
Criterion C: The disturbance does not occur exclusively during the course of anorexia nervosa or bulimia nervosa, and there is no evidence of a disturbance in the way body weight or shape is experienced.
No fear of weight gain. No body image distortion. No compensatory behaviors. Wants to gain weight. MET.
Criterion D: The eating disturbance is not attributable to a concurrent medical condition or another mental disorder. When occurring in the context of another condition, the eating disturbance exceeds what is routinely associated with that condition.
No GI pathology identified. ADHD is present but does not account for selective sensory-based food refusal. MET.
Diagnostic Conclusion
Avoidant/Restrictive Food Intake Disorder (F50.82)
The presentation is consistent with ARFID, sensory sensitivity subtype. The restriction is driven by texture/sensory aversions with childhood onset, absent body image pathology, and intact weight gain motivation. Anorexia Nervosa is excluded by the absence of weight/shape concerns and the sensory-driven (rather than calorie-driven) food selection.
Teaching Points
- ARFID (introduced in DSM-5) replaces and expands upon DSM-IV's "Feeding Disorder of Infancy or Early Childhood." It is diagnosed across the lifespan and encompasses three presentations: (1) sensory sensitivity (this patient), (2) fear of aversive consequences (choking, vomiting), and (3) lack of interest in eating.
- The body image assessment is the critical differentiator. A single direct question often suffices: "If you could wave a magic wand and eat any food without restriction, would you?" The ARFID patient says yes. The AN patient reveals reluctance because increased intake threatens their weight/shape goals.
- ARFID frequently co-occurs with ASD, ADHD, and anxiety disorders. The sensory processing profile in this patient (texture aversions, sensitivity to clothing tags and loud noises) is consistent with this pattern. The clinician should screen for neurodevelopmental conditions when ARFID is identified.
- Treatment approaches differ: AN requires weight restoration with cognitive work targeting body image and weight phobia. ARFID responds to gradual sensory exposure (food chaining), CBT-AR (CBT for ARFID), and addressing the underlying sensory processing difficulties. Applying AN treatment models (emphasizing body image) to an ARFID patient is clinically inappropriate.
- Medical monitoring is essential for both conditions: BMI 16.8 with nutritional deficiencies requires monitoring regardless of diagnosis. The medical urgency is determined by the degree of malnutrition, not the psychiatric label.