Anorexia Nervosa DSM-5

Diagnostic Criteria

A) restriction of energy intake relative to needs, leading to significantly low body weight for the individual’s age, sex, developmental trajectory, and physical health.

• significantly low = less than minimally normal, or less than minimally expected in the case of kids/adolescents

B) intense fear of gaining weight / becoming fat, or persistent behaviour that interferes w/ weight gain even when at a significantly low weight

C) a disturbance in the way that the individual experiences their body weight / shape, too much important placed on body weight / shape wrt self-image / self-regard, or persistent inability to see the seriousness of current low body weight

Subtypes

• restricting type: lack of binge-eating / purging behaviour over the last 3 mos. weight loss is primarily achieved thru excessive exercise, dieting, or fasting

• binge-eating/purging type: during the last 3 months, the pt has had recurrent episodes of bingeing or purging behaviours (eg: self-induced vomiting, misuse of laxatives / diuretics / enemas)

  • most people w/ this subtype binge + purge, but some just purge

• crossover between subtypes is common; should be used to describe current symptoms and not longitudinal course of illness

Diagnostic Features

• usually criteria A is assessed by BMI

  • in adults, lower than 17 is significantly low; between 17 - 18.5 may be determined sig. low if other physiological info supports that judgement

  • in kids/adolescents: BMI-for-age percentile — below 5th percentile is underweight, but BMI above this percentile may still be sig. low if they’re failing to maintain expected growth trajectory

• people that aren’t underweight by population-based standards can’t be diagnosed w/ anorexia nervosa; can be diagnosed w/ other specified feeding or eating disorder (atypical anorexia nervosa)

• fear of being fat / gaining weight is not alleviated by weight loss and may even increase

• young people (+ some adults) may not recognise their fear of weight gain — may require clinician inference (history, observational data, etc.)

• usually brought to professional attention by concerned family members after marked weight loss or failing to gain weight

• if self-referred, usually done so bc of distress over somatic + psychological effects of starvation

• frequently lack insight

Associated Features

• potentially life-threatening medical conditions

• physiological disturbances

• depressive signs / symptoms: also appear in undernourished people without anorexia, so may be effect of starvation — but may also be severe enough for additional diagnosis of MDD

• obsessive-compulsive features related to food (preoccupation w/ thoughts of food, collecting recipes, hoarding food, etc)

• common thoughts / behaviours: concerns about eating in public, feeling ineffective, strong urge to control one’s environment, inflexible thinking, limited social spontaneity, overly restrained emotional expression

• binge-eating/purging type: higher rates of impulsivity, more likely to abuse substances

Prevalence

• 12 mo. in US: 0.0 - 0.05%

  • much higher in women (0 - 0.08%) than men (0 - 0.01%)

• lifetime in US: .6 - .8%

  • W: 0.9 - 1.42%; M: 0.12 - 0.3%

• most prevalent in post-industrialised, high-income countries — but appears to be increasing in global south

Development + Course

• usually onset is during adolescence or early adulthood

• often onset is associated w/ stressful life event

• rare to begin before puberty or after 40

• course + outcome is v. variable

• younger people likelier to have atypical features

• older people more likely to have longer duration + more signs and symptoms of longstanding disorder

• many people have period of changed eating behaviour before meeting full symptom criteria

• some recover fully after 1 episode, some have relapse after WG, + some have chronic course over many years 

• most experience remission within 5 years

• mortality rate: 5% per decade — most commonly from medical complications from disorder or from suicide

Risk + Prognostic Factors

• temperamental: developing anxiety disorder or showing obsessional traits in childhood

• environmental: belonging to cultures, settings, jobs, or hobbies where thinness is valued / encouraged

• genetic: higher risk in biological relatives of people w/ anorexia; abnormal reward processing in brain

Functional Consequences

• 18x suicide risk

• ¼ to 1/3 have experienced suicidal ideation

• 9 - 25% have attempted suicide

  • potential reasons: greater exposure to sexual abuse, impaired decision-making, high rates of nonsuicidal self-injury, comorbidity w/ mood disorders

• wide range of functional limitations, from little change to social isolation or failure to fulfill academic / career potential

Differential Diagnoses

• NOTE: important in all cases to consider other possible causes of significant low body weight / significant weight loss when presenting features are atypical

• medical conditions

• major depressive disorder

• schizophrenia

• substance use disorders

• social anxiety disorder

• obsessive-compulsive disorder

• body dysmorphic disorder

• bulimia nervosa

• avoidant / restrictive food intake disorder

Differential Diagnosis: Medical Conditions

serious weight loss can occur in medical conditions, but usually shouldn’t come with a fear of weight gain, behaviours that prevent appropriate weight gain, or body image disturbances. acute weight loss from medical conditions can sometimes be followed by onset / recurrence of anorexia, which is initially masked by comorbid condition

Differential Diagnosis: Major Depressive Disorder

severe weight loss may occur but generally doesn’t come with a desire for weight loss or a fear of weight gain

Differential Diagnosis: Schizophrenia

may show strange eating behaviours or experience significant weight loss, but rarely show fear of weight gain or body image disturbances

Differential Diagnosis: Substance Use Disorders

may have low weight bc of bad nutritional intake, but generally don’t fear weight gain or have body image disturbance. if they’re abusing substances that reduce appetite (eg: cocaine, stimulants) + endorse a fear of weight gain, they should be carefully evaluated for potential comorbid anorexia nervosa

Differential Diagnosis: Social Anxiety Disorder

overlap in potential humiliation / embarrassment to be seen eating in public. if social fears are only about eating behaviours, only anorexia should be diagnosed; if they also have unrelated social fears, an additional diagnosis of social anxiety disorder should be made

Differential Diagnosis: Obsessive-Compulsive Disorder

potential overlap in obsessions / compulsions related to food — OCD should only be considered as another diagnosis if there are non-food-related obsessions / compulsions as well

Differential Diagnosis: Body Dysmorphic Disorder

potential overlap in preoccupation w/ imagined issue in appearance. additional diagnosis of BDD should only be considered if there’s a distortion unrelated to body shape / size.

Differential Diagnosis: Bulimia Nervosa

overlap w/ binge-eating/purging subtype in recurrent bingeing / purging behaviours + obsession w/ body shape + weight. however, people w/ bulimia nervosa maintain body weight at or above a minimally normal level

Differential Diagnosis: Avoidant/Restrictive Food Intake Disorder

ppl w/ ARFID may have significant weight loss or a nutritional deficiency, but won’t have a fear of weight gain or body image disturbances

Comorbidity

• common: bipolar, depressive, + anxiety disorders

• many report anxiety disorder / symptoms of anxiety prior to anorexia onset

• OCD more common in restricting type

• alcohol use disorder + other substance use disorders more common in binge-eating/purging

Treatment: Psychotherapy

• family-based therapy (FBT): parents play active role in return to healthy weight + normalising eating behaviours; most evidence-based in adolescents

• CBT: targets distorted beliefs about body weight, shape, + food; can be adapted for relapse prevention after weight restoration. works in adults + older adolescents

• other approaches

  • DBT: for people w/ high impulsivity or comorbid mood / self-injury behaviours

  • supportive psychotherapy: focus on emotional support, motivation, + coping strategies

  • interpersonal psychotherapy (IPT): can address relationship stressors that maintain disordered eating

Treatment: Meds

• none specifically approved for anorexia

• off-label uses

  • SSRIs: can help w/ comorbid depression / anxiety, more effective after partial weight restoration

  • atypical antipsychotics: can decrease obsessive thoughts about body image + support weight gain in some patients

  • other meds: can be used cautiously for comorbid conditions