A 38-year-old woman comes to the physician for a follow-up visit. She has a 2-year history of depressed mood and fatigue accompanied by early morning awakening. One week ago, she started feeling a decrease in her need for sleep and now feels rested after about 5 hours of sleep per night. She had two similar episodes that occurred 6 months ago and a year ago, respectively. She reports increased energy and libido. She has a 4-kg (8.8-lb) weight loss over the past month. She does not feel the need to eat and says she derives her energy ""from the universe"". She enjoys her work as a librarian. She started taking fluoxetine 3 months ago. On mental exam, she is alert and oriented to time and place; she is irritable. She does not have auditory or visual hallucinations. Physical examination shows no abnormalities. Which of the following is the most likely diagnosis?

Medication-induced bipolar disorder

A 20-year-old female presents to student health at her university for excessive daytime sleepiness. She states that her sleepiness has caused her to fall asleep in all of her classes for the last semester, and that her grades are suffering as a result. She states that she normally gets 7 hours of sleep per night, and notes that when she falls asleep during the day, she immediately starts having dreams. She denies any cataplexy. A polysomnogram and a multiple sleep latency test rule out obstructive sleep apnea and confirm her diagnosis. She is started on a daytime medication that acts both by direct neurotransmitter release and reuptake inhibition. What other condition can this medication be used to treat?

Attention-deficit hyperactivity disorder

A 28-year-old male presents to trauma surgery clinic after undergoing an exploratory laparotomy, femoral intramedullary nail, and femoral artery vascular repair 3 months ago. He suffered multiple gunshot wounds as a victim of a drive-by shooting. He is progressing well with well-healed surgical incisions on examination. He states during his clinic visit that he has been experiencing 6 weeks of nightmares where he "relives the day he was shot." The patient also endorses 6 weeks of flashbacks to "the shooter pointing the gun at him" during the daytime as well. He states that he has had difficulty sleeping and cannot concentrate when performing tasks. Which of the following is the most likely diagnosis?

Post-traumatic stress disorder (PTSD)

A 23-year-old woman is brought to the physician by her father because of irritability, mood swings, and difficulty sleeping over the past 10 days. A few days ago, she quit her job and spent all of her savings on supplies for a “genius business plan.” She has been energetic despite sleeping only 1–2 hours each night. She was diagnosed with major depressive disorder 2 years ago. Mental status examination shows pressured speech, a labile affect, and flight of ideas. Throughout the examination, she repeatedly states “I feel great, I don't need to be here.” Urine toxicology screening is negative. Which of the following is the most likely diagnosis?

Attention-deficit hyperactivity disorder

Catatonia across disorders for USMLE Step 3: High-Yield Psychiatry Lessons

Catatonia Signs - The Frozen Patient

A distinct psychomotor syndrome involving a marked decrease in environmental reactivity. While often linked to mood and psychotic disorders, it can also stem from medical conditions. Diagnosis requires ≥3 specific signs.

Stupor/Immobility: Profound lack of movement and response.
Mutism: Verbally unresponsive.
Posturing/Catalepsy: Actively holding a posture against gravity.
Waxy Flexibility: Limb remains in the position it is placed.
Negativism: Opposition or no response to external stimuli.
Echolalia/Echopraxia: Mimicking another's speech/movements.

⭐ The Lorazepam Challenge (1-2 mg IV/IM) is a crucial diagnostic and therapeutic tool. A positive response (rapid improvement) helps confirm the diagnosis.

Etiology - More Than Madness

Catatonia stems from diverse medical and psychiatric conditions, challenging the misconception of it being exclusive to schizophrenia. It is most commonly associated with mood disorders.

Psychiatric:
- Bipolar Disorder (most frequent cause)
- Major Depressive Disorder
- Schizophrenia
Neurologic:
- Neuroleptic Malignant Syndrome (NMS)
- Stroke, tumors, encephalitis
Medical/Systemic:
- Metabolic (e.g., uremia, DKA)
- Infectious (e.g., sepsis)
- Autoimmune (e.g., lupus)

⭐ While often linked to psychosis in media, catatonia is diagnosed more frequently in patients with bipolar disorder than in those with schizophrenia.

Diagnosis & Workup - The Clinical Detective

DSM-5 Criteria: Diagnosis requires ≥3 of 12 psychomotor features.
Diagnostic Flow:

⭐ The Lorazepam Challenge Test is both diagnostic and therapeutic. A positive response (rapid, temporary symptom resolution) strongly supports a catatonia diagnosis over Neuroleptic Malignant Syndrome (NMS).

Management - Breaking the Spell

1st Line: Benzodiazepines (e.g., Lorazepam 1-2 mg IV/IM, titrated). Response often seen within minutes.
2nd Line/Severe: Electroconvulsive Therapy (ECT) is the most definitive and effective treatment, especially in malignant catatonia.
⚠️ AVOID Antipsychotics: Can worsen catatonia and increase risk of Neuroleptic Malignant Syndrome (NMS).

Electroconvulsive Therapy (ECT) for psychiatric disorders

⭐ The "Lorazepam Challenge" is both diagnostic and therapeutic. A dramatic, temporary resolution of symptoms after 1-2 mg IV lorazepam strongly supports the diagnosis.

High-Yield Points - ⚡ Biggest Takeaways

Catatonia is a psychomotor syndrome seen across psychiatric (mood, psychotic) and medical conditions.

Diagnosis requires ≥3 of 12 symptoms like mutism, stupor, and waxy flexibility.

The lorazepam challenge test is both diagnostic and therapeutic, often causing rapid improvement.

First-line treatment is benzodiazepines; ECT is the most definitive treatment, especially for malignant catatonia.

Always differentiate from Neuroleptic Malignant Syndrome (NMS), which presents similarly.

Malignant catatonia is a life-threatening emergency with fever and autonomic instability.

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