Step 2 CK · Psychiatry

Child, Neurodevelopmental & Eating Disorders

Name: Child, Neurodevelopmental & Eating Disorders
Creator: Veli Bakalov, MD

From ADHD and autism to anorexia and the perils of refeeding

Psychiatry·Child & Adolescent Psychiatry·4 min read·9 high-yield points·Reviewed by Veli Bakalov, MD @HemeOncBuddy

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High-yield

ADHD = ≥6 inattentive and/or hyperactive-impulsive symptoms for ≥6 months in ≥2 settings with onset before age 12; stimulants (methylphenidate, amphetamines) are first-line.
ADHD non-stimulants are atomoxetine (norepinephrine reuptake inhibitor) and α2 agonists (guanfacine, clonidine); stimulants cause appetite loss, insomnia, and modest growth slowing, so screen cardiac history and track growth.
Autism = social-communication deficits plus restricted, repetitive behaviors from early development; M-CHAT at 18 and 24 months, ABA therapy, risperidone or aripiprazole for irritability.
Tourette = multiple motor tics plus ≥1 vocal tic for >1 year with onset before 18; comorbid OCD and ADHD; habit-reversal therapy first, then α2 agonists, antipsychotics, or tetrabenazine.
ODD = angry defiance toward authority without rights violations; conduct disorder = violating others' rights (aggression, cruelty, theft); conduct disorder before 15 is required for antisocial PD at ≥18.
Anorexia = significantly low weight with the highest psychiatric mortality → nutritional rehabilitation plus psychotherapy; bulimia = normal weight with purging signs (parotid swelling, Russell sign, hypokalemic alkalosis) → CBT plus fluoxetine, never bupropion.
Refeeding syndrome hallmark is hypophosphatemia (insulin drives phosphate, K, and Mg into cells) → refeed slowly and replete phosphate, K, Mg, and thiamine.
Binge eating disorder (binges without compensation) → CBT, SSRIs, or lisdexamfetamine; body dysmorphic disorder → SSRI plus CBT, not cosmetic procedures.
Enuresis (age ≥5, ≥2×/week for 3 months): rule out UTI and diabetes; enuresis alarm or oral desmopressin first-line (family choice), imipramine third.

ADHD

Diagnosis. ADHD requires ≥6 symptoms of inattention and/or hyperactivity-impulsivity lasting at least 6 months, present in ≥2 settings (such as home and school), with onset before age 12 and functional impairment. Check hearing and vision and consider sleep problems, absence seizures, and learning disorders before labeling a child inattentive. Comorbid learning, oppositional, and anxiety disorders are common.

Treatment. Stimulants are first-line pharmacotherapy from school age onward, combined with behavioral interventions; in preschoolers, parent training in behavior management comes first. Screen cardiac history (syncope, exertional symptoms, family history of sudden death) before starting a stimulant.

ADHD medications

Class	Examples	Role	Watch for
Stimulants	Methylphenidate, amphetamines	First-line; fastest and most effective	Appetite suppression, insomnia, modest growth slowing, misuse or diversion
Norepinephrine reuptake inhibitor	Atomoxetine	Non-stimulant alternative; not a controlled substance	GI upset; boxed warning for suicidal thinking
α2 agonists	Guanfacine, clonidine	Non-stimulant alternative or adjunct; helpful with tics	Sedation, hypotension, rebound hypertension if stopped abruptly

Monitor height and weight on stimulants and consider drug holidays if growth slows.

Autism and tic disorders

Autism spectrum disorder requires persistent deficits in social communication and interaction PLUS restricted, repetitive patterns of behavior or interests, present early in development. Screen every child with the M-CHAT at 18 and 24 months; a positive screen prompts a formal diagnostic evaluation plus audiology; once ASD is diagnosed, offer genetic testing (chromosomal microarray, fragile X). Early intensive behavioral therapy (applied behavior analysis, ABA) is the mainstay; risperidone or aripiprazole is FDA-approved for associated irritability and aggression.

Tourette disorder is multiple motor tics AND at least one vocal tic, present for more than 1 year with onset before age 18. It is strongly comorbid with OCD and ADHD. Treatment starts with habit-reversal therapy, then α2 agonists, antipsychotics (fluphenazine, pimozide, haloperidol, aripiprazole), or the VMAT2 inhibitor tetrabenazine (off-label).

Disruptive behavior disorders

ODD vs conduct disorder vs antisocial personality disorder

Feature	Oppositional defiant disorder	Conduct disorder	Antisocial personality disorder
Core behavior	Angry or irritable mood, argumentative and defiant, vindictive	Repetitive violation of others' rights and social norms	Pervasive disregard for others' rights
Examples	Defiance of parents and teachers; no major rights violations	Aggression to people or animals, destruction, deceit or theft, serious rule-breaking	Deceit, criminality, impulsivity, lack of remorse
Timing	≥6 months	Childhood or adolescence (before 18)	Age ≥18 with conduct disorder before 15

Management. ODD and conduct disorder are treated with parent management training and psychotherapy, addressing comorbid ADHD or learning problems. Conduct disorder that begins before age 15 is a prerequisite for antisocial personality disorder, which cannot be diagnosed before age 18.

Eating disorders

Anorexia vs bulimia vs binge eating disorder

Feature	Anorexia nervosa	Bulimia nervosa	Binge eating disorder
Weight	Significantly low	Normal or overweight	Often overweight or obese
Behavior	Energy restriction; restricting or binge-eating/purging subtype	Binges plus compensation (vomiting, laxatives, fasting, exercise) at least weekly for 3 months	Binges with loss of control at least weekly for 3 months, WITHOUT compensation
Clues	Bradycardia, hypotension, lanugo, amenorrhea, osteoporosis	Parotid enlargement, Russell sign, dental erosion, hypokalemic hypochloremic metabolic alkalosis	Guilt and distress after binges
Treatment	Nutritional rehabilitation plus psychotherapy; SSRIs not first-line	CBT plus fluoxetine (60 mg, best evidence)	CBT; SSRIs; lisdexamfetamine is FDA-approved

Anorexia nervosa is energy restriction leading to significantly low body weight, with intense fear of weight gain and distorted body image. It is medically more severe than bulimia and carries the highest mortality of any psychiatric disorder, from arrhythmia, electrolyte derangements, and suicide. Hospitalize for unstable vital signs, severe bradycardia, orthostasis, electrolyte abnormalities, or very low weight. Family-based therapy is preferred for adolescents, and SSRIs work poorly in a starved brain.

Bupropion is contraindicated in bulimia and anorexia: purging-related electrolyte shifts lower the seizure threshold further.

Refeeding syndrome. Reintroducing carbohydrate to a malnourished patient triggers an insulin surge that drives phosphate, potassium, and magnesium into cells. The hallmark is HYPOphosphatemia, which can cause arrhythmias, heart failure, and death. Prevent it by refeeding slowly, checking electrolytes frequently in the first days, and repleting phosphate, potassium, magnesium, and thiamine.

Chronic malnutritionDepleted total-body stores.
Carbohydrate refeedingInsulin surge.
Intracellular shiftPhosphate, K, and Mg fall.
HypophosphatemiaArrhythmia, heart failure.

Refeeding syndrome cascade

Body dysmorphic disorder and enuresis

Body dysmorphic disorder is preoccupation with a perceived physical flaw that is slight or unobservable to others, plus repetitive behaviors such as mirror-checking, grooming, or reassurance-seeking. It is an OCD-related disorder; treat with an SSRI plus CBT. Cosmetic procedures do not help and often make it worse.

Enuresis is repeated involuntary voiding at least twice weekly for 3 months in a child aged 5 or older; primary nocturnal enuresis (never consistently dry) is most common. Rule out UTI and diabetes with a urinalysis. Secondary enuresis, after a dry period, should prompt a search for stressors, infection, diabetes, or constipation.

Enuresis alarmFirst-line option with the best long-term cure rate and lowest relapse.
Desmopressin (DDAVP)Also first-line, chosen by family preference; works fast, good for short-term needs such as sleepovers or when an alarm is impractical; oral form only (not intranasal); no fluids from 1 hour before bedtime to 8 hours after the dose (hyponatremia).
ImipramineThird-line TCA; dangerous in overdose.

Stepwise treatment of nocturnal enuresis