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PMHS: Assessment and Diagnosis

PMHS · Work through your exam, one topic at a time.

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Assessment and Diagnosis

What this domain tests

This domain covers screening versus diagnosis, validated instruments and the ages they were built for, DSM-5-TR criteria applied developmentally, medical and substance-related mimics, comorbidity, and structured suicide risk assessment.

Screening tools worth knowing

  • Developmental: ASQ-3; autism-specific M-CHAT-R/F at 18 and 24 months.
  • Depression: PHQ-2 then PHQ-9 modified for adolescents (PHQ-A); USPSTF recommends screening ages 12-18.
  • Anxiety: SCARED, GAD-7, RCADS; USPSTF recommends screening ages 8-18.
  • ADHD: Vanderbilt parent and teacher forms, SNAP-IV, Conners. Teacher input is not optional.
  • Substance use: CRAFFT for ages 12-21.
  • Broad function: PSC-17 or SDQ.

Diagnosis and differential

  • DSM-5-TR requires symptom count, duration, impairment, and exclusion of other causes. A screen score alone never satisfies this.
  • Always ask about mania before treating irritability or depression: episodic course, decreased need for sleep, grandiosity, and racing thoughts change the plan entirely.
  • Medical mimics: obstructive sleep apnea and tonsillar hypertrophy, iron deficiency, hypothyroidism, lead, B12 deficiency, hearing or vision deficits, caffeine and energy drinks, cannabis, stimulants, steroids, anticholinergics.
  • Comorbidity is the rule: ADHD with oppositional defiant disorder and anxiety, depression with anxiety, anxiety with substance use.

Suicide risk

Endorsing PHQ item 9 is a prompt, not a risk assessment. Follow with a structured tool such as the Ask Suicide-Screening Questions, then assess ideation, plan, intent, access to means, prior attempts, and protective factors, and document it.

Worked example

A 14-year-old presents with irritability and falling grades. Reasoning: screen with PHQ-A, ask about sleep and energy, use CRAFFT, and check for snoring or daytime somnolence plus thyroid signs if fatigue dominates. Ask directly about mania and about suicidal ideation with a structured tool. Irritability plus declining grades plus a positive depression screen supports major depression only after mimics and bipolarity are excluded.

Traps that cost marks

  • Diagnosing ADHD without teacher ratings or without checking sleep.
  • Attributing everything to adolescence and skipping screening.
  • Using the PHQ-9 total as the entire suicide assessment.