A mother brings her 3-year-old son to the doctor because she is worried that he might be harming himself by constantly banging his head on the wall. He has been exhibiting this behavior for a few months. She is also worried because he has started to speak less than he used to and does not respond when his name is called. He seems aloof during playtime with other children and seems to have lost interest in most of his toys. What is the most likely diagnosis?

Attention deficit hyperactivity disorder

A 4-year-old boy is brought to the physician because of non-fluent speech. His mother worries that his vocabulary is limited for his age and because he cannot use simple sentences to communicate. She says he enjoys playing with his peers and parents, but he has always lagged behind in his speaking and communication. His speech is frequently not understood by strangers. He physically appears normal. His height and weight are within the normal range for his age. He responds to his name, makes eye contact, and enjoys the company of his mother. Which of the following is the most appropriate next step in management?

Evaluate response to methylphenidate

A 9-year-old boy is brought to a pediatric psychologist by his mother because of poor academic performance. The patient’s mother mentions that his academic performance was excellent in kindergarten and first grade, but his second and third-grade teachers complain that he is extremely talkative, does not complete schoolwork, and frequently makes careless mistakes. They also complain that he frequently looks at other students or outside the window during the class and is often lost during the lessons. At home, he is very talkative and disorganized. When the pediatrician asks the boy his name, he replies promptly. He was born at full term by spontaneous vaginal delivery. He is up-to-date on all vaccinations and has met all developmental milestones on time. A recent IQ test scored him at 95. His physical examination is completely normal. When he is asked to read from an age-appropriate children’s book, he reads it fluently and correctly. Which of the following is the most likely diagnosis in this patient?

Attention-deficit/hyperactivity disorder

A 6-year-old boy presents to the pediatrician with his parents. He is fully vaccinated and met most developmental milestones. His fine motor milestones are delayed; at present, he cannot eat by himself and has difficulty in self-dressing. His intelligence quotient (IQ) is 65. He listens quietly while spoken to and engages in play with his classmates. He neither talks excessively nor remains mute, but engages in normal social conversation. There is no history of seizures and he is not on any long-term medical treatment. On his physical examination, his vital signs are stable. His height and weight are normal for his age and sex, but his occipitofrontal circumference is less than the 3rd percentile for his age and sex. His neurologic examination is also normal. Which of the following is the most likely diagnosis?

Attention deficit hyperactivity disorder

A 4-year-old boy is brought to a pediatrician by his parents for a consultation after his teacher complained about his inability to focus or make friends at school. They mention that the boy does not interact well with others at home, school, or daycare. On physical examination, his vital signs are stable with normal weight, height, and head circumference for his age and sex. His general examination and neurologic examination are completely normal. A recent audiological evaluation shows normal hearing, and intellectual disability has been ruled out by a clinical psychologist. Which of the following investigations is indicated as part of his diagnostic evaluation at present?

Autism spectrum disorder screening and developmental assessment

Magnetic resonance imaging (MRI) of brain

Positron Emission Tomography (PET) scanning of head

A 3-year-old girl is brought to the physician for a well-child examination. She was born at term and has been healthy since. She can climb up and down the stairs and can pedal a tricycle. She has difficulty using a spoon to feed herself but can copy a line. She speaks in 2- to 3-word sentences that can be understood by most people. She is selfish while playing with children her age and throws tantrums quite often. She cannot put on her own shoes and socks. She does not tolerate separation from her parents. She is at 60th percentile for height and weight. Physical examination including neurologic examination reveals no abnormalities. Which of the following is the most appropriate assessment of her development?

Fine motor: Delayed | Gross motor: Normal | Language: Normal | Social skills: Delayed

Fine motor: Normal | Gross motor: Normal | Language: Delayed | Social skills: Delayed

Fine motor: Delayed | Gross motor: Delayed | Language: Normal | Social skills: Normal

Fine motor: Normal | Gross motor: Delayed | Language: Normal | Social skills: Delayed

Fine motor: Normal | Gross motor: Delayed | Language: Delayed | Social skills: Normal

True about Fragile X syndrome is

10% Female carriers mentally retarded

Triple nucleotide CAG Sequence mutation

Autosomal dominant inheritance pattern

A 4-year-old boy presents with language delay, toe-walking, hand-flapping, and intense interest in trains. He makes poor eye contact but occasionally engages in joint attention with his mother when looking at trains. He has sensory sensitivities to loud noises. He can identify all letters and numbers but cannot have reciprocal conversations. His Childhood Autism Rating Scale (CARS) score is borderline. His parents request your opinion on diagnosis and intervention priorities given diagnostic uncertainty and limited early intervention resources in their area.

Presume autism spectrum disorder and implement evidence-based early interventions while monitoring

Diagnose autism spectrum disorder and begin comprehensive ABA therapy immediately

Diagnose language disorder and focus resources on communication training

Refer to genetics for testing before committing to diagnosis or intervention

Delay diagnosis pending further developmental assessment and prioritize speech therapy

Learning disorders for USMLE Step 3: High-Yield Psychiatry Lessons

Specific Learning Disorder - Brain's Learning Quirks

A neurodevelopmental disorder with persistent difficulties in learning keystone academic skills (reading, writing, math), despite normal intelligence. Performance is substantially below that expected for age.
Symptoms must persist for ≥ 6 months despite targeted interventions.
Key Specifiers:
- With impairment in reading (dyslexia)
- With impairment in written expression (dysgraphia)
- With impairment in mathematics (dyscalculia)

⭐ ADHD is a very common comorbidity, present in approximately 20-30% of children with a specific learning disorder.

Dyslexia - Word Jumble Rumble

A specific learning disorder characterized by difficulties with accurate or fluent word recognition, poor decoding, and poor spelling abilities.
Core deficit: Phonological processing - trouble manipulating sounds of language. This impacts decoding (sounding out words).
Presents as slow, effortful reading. Intelligence is typically normal.
Diagnosis: Standardized testing confirms reading achievement is substantially below that expected for the individual’s chronological age.

⭐ High comorbidity with ADHD is frequently seen; always screen for co-existing conditions.

Dyscalculia & Dysgraphia - Number Numbness, Scrawl Crawl

Dyscalculia (Impairment in Mathematics)
- Difficulty understanding number concepts, memorizing math facts, or performing accurate calculations.
- Presents with trouble in counting, number sense, and mathematical reasoning.
- 📌 Nicknamed "math dyslexia."
Dysgraphia (Impairment in Written Expression)
- Persistent difficulty with handwriting, spelling, and organizing thoughts on paper.
- Features illegible/slow writing, poor grammar, and weak paragraph structure.
Diagnosis
- Requires performance on standardized tests substantially below age-level norms, not explained by other deficits.
- Management involves specialized educational strategies.

⭐ High-Yield: These disorders frequently co-occur with dyslexia and ADHD, complicating diagnosis and management.

Workup & Management - Spotting & Supporting

Psychoeducational testing is the cornerstone for diagnosis, assessing intelligence (IQ) against specific academic skills.
Crucial to rule out sensory deficits (hearing/vision) and inadequate schooling.
Management centers on an Individualized Education Program (IEP) or 504 Plan.
- Provides accommodations: extra time, quiet rooms, assistive technology (e.g., text-to-speech).
- Involves specialized, direct instruction targeting the deficit (e.g., phonics-based methods for dyslexia).

⭐ Diagnosis requires academic skills substantially and quantifiably below the individual's chronological age, causing significant functional impairment, confirmed by standardized testing.

High‑Yield Points - ⚡ Biggest Takeaways

ADHD requires inattention and/or hyperactivity-impulsivity before age 12, causing impairment in ≥2 settings; first-line treatment is stimulants.

Autism Spectrum Disorder (ASD) is defined by deficits in social communication and restricted, repetitive behaviors.

Specific Learning Disorder involves difficulties with academic skills (e.g., reading, writing, math) despite normal intelligence.

For all, symptoms must cause significant functional impairment to warrant diagnosis.

Differentiate from intellectual disability, which involves global deficits in intellectual and adaptive functioning.

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