9.3 Psychiatric Emergencies & Substance Use Disorders
Key Takeaways
- Suicide risk assessment uses the SAD PERSONS mnemonic; patients at imminent risk of self-harm who refuse voluntary admission require involuntary psychiatric hold and removal of access to means.
- Alcohol withdrawal is managed using symptom-triggered benzodiazepines via the CIWA-Ar protocol; short-acting agents (lorazepam, oxazepam, temazepam) are preferred in hepatic impairment or elderly.
- Acute opioid overdose presents with respiratory depression, miosis, and coma; treat with intravenous or intranasal naloxone, titrating to restore respiratory rate and oxygenation rather than full alertness.
- Chronic substance use disorder maintenance includes acamprosate (preferred in liver disease) and naltrexone for alcohol use disorder, and methadone or buprenorphine for opioid use disorder.
Psychiatric Emergencies & Substance Use Disorders
Psychiatric emergencies and substance use disorders are high-stakes topics on the USMLE Step 3. The focus is on clinical risk stratification, diagnostic workups, acute intoxication/withdrawal protocols, and chronic maintenance strategies.
Suicide Risk Assessment
Suicide risk assessment requires active, direct questioning regarding suicidal ideation, intent, plan, and access to lethal means. Risk factors can be recalled using the SAD PERSONS mnemonic: Sex (male), Age (elderly/adolescent), Depression, Previous attempt (single strongest predictor of future completed suicide), Ethanol/substance abuse, Rational thinking loss (psychosis), Social support lacking, Organized plan, No spouse, and Sickness. Clinicians must also evaluate protective factors, which include strong social support, active coping strategies, therapeutic alliance, religious or moral objections, and having young children at home.
Management is determined by the severity of risk. Patients with active suicidal ideation, intent, and a specific plan must not be left alone. Immediate safety planning is required, and access to lethal means (such as firearms and stockpiled medications) must be removed. If a patient is at imminent risk of self-harm and refuses voluntary hospitalization, the clinician must initiate an involuntary psychiatric hold to ensure safety. Voluntary admission is preferred when the patient is cooperative, possesses adequate insight, and agrees to the treatment plan.
Acute Psychosis and Catatonia
Acute psychosis presents with delusions, hallucinations, disorganized speech, or grossly disorganized behavior. The initial step is to rule out medical or substance-induced etiologies. Workup includes CBC, BMP, TSH, vitamin B12, urine drug screen, and a head CT if focal neurological signs or trauma are present.
For acute agitation or violent behavior, the primary goal is to ensure the safety of the patient and staff. Pharmacological options include intramuscular second-generation antipsychotics (olanzapine, ziprasidone) or haloperidol plus lorazepam, with diphenhydramine added to prevent acute extrapyramidal side effects.
Catatonia is a severe motor syndrome associated with schizophrenia, mood disorders, or medical conditions, presenting with mutism, posturing, waxy flexibility, echolalia, and stupor. The diagnosis is confirmed via a lorazepam challenge test (intravenous administration of 1-2 mg of lorazepam resulting in temporary improvement). First-line treatment for catatonia is benzodiazepines (lorazepam); if refractory or in the case of malignant catatonia (associated with autonomic instability and hyperthermia), electroconvulsive therapy (ECT) is indicated.
Clinicians must monitor closely for neuroleptic malignant syndrome (NMS), a life-threatening reaction to antipsychotics characterized by hyperthermia, altered mental status, autonomic instability, elevated creatine kinase, and 'lead-pipe' rigidity. Treatment requires discontinuing all antipsychotics, initiating supportive care (cooling blankets, IV fluids), and administering dantrolene or bromocriptine in severe cases.
Alcohol Withdrawal Protocol
Alcohol withdrawal occurs due to chronic receptor adaptation: down-regulation of inhibitory GABA receptors and up-regulation of excitatory NMDA receptors. Abrupt cessation of alcohol results in sudden, unchecked CNS hyperexcitablity.
The clinical withdrawal timeline is highly structured:
- Mild Withdrawal (6 to 24 hours): Tremors, anxiety, headache, diaphoresis, palpitations, intact orientation.
- Withdrawal Seizures (12 to 48 hours): Generalized tonic-clonic seizures, often single or in a brief flurry.
- Alcoholic Hallucinosis (12 to 48 hours): Visual or auditory hallucinations, stable vitals, intact sensorium.
- Delirium Tremens (48 to 96 hours): Autonomic instability (fever, tachycardia, hypertension), disorientation, agitation, hallucinations; carries 5% mortality.
Management centers on the Clinical Institute Withdrawal Assessment for Alcohol (CIWA-Ar) protocol, which guides symptom-triggered administration of benzodiazepines. Symptomatic dosing is superior to fixed-schedule dosing because it requires lower total doses of benzodiazepines and shortens the hospital stay. Long-acting agents like diazepam or chlordiazepoxide are preferred in most patients due to self-tapering pharmacokinetics. However, in patients with hepatic impairment or the elderly, short-acting agents that do not undergo hepatic oxidation are preferred: lorazepam, oxazepam, or temazepam (recalled by the mnemonic 'LOT'). Supportive care must include intravenous thiamine administered before any glucose-containing fluids to prevent Wernicke encephalopathy.
Opioid Overdose and Withdrawal
Opioid overdose presents with the classic triad of altered mental status, miosis (pinpoint pupils), and respiratory depression. Decreased bowel sounds and hypothermia are also common. The immediate management priority is securing the airway and supporting ventilation. Intravenous or intranasal naloxone (a competitive opioid antagonist) is administered. The titration goal for naloxone is to restore adequate respiratory rate and oxygenation, not necessarily full consciousness, to avoid precipitating severe, acute withdrawal symptoms (agitation, vomiting, diarrhea, diaphoresis).
In contrast to sedative-hypnotic withdrawal, acute opioid withdrawal is extremely uncomfortable (rhinorrhea, lacrimation, yawning, piloerection, abdominal cramps, diarrhea, dilated pupils) but is not inherently life-threatening. Symptomatic management with clonidine (for autonomic symptoms), loperamide (for diarrhea), and NSAIDs is standard.
Chronic Management of Substance Use Disorders
Long-term management combines pharmacotherapy and psychosocial support.
Alcohol Use Disorder: First-line medications are acamprosate and naltrexone. Acamprosate (a glutamate modulator) is preferred in patients with liver disease but is contraindicated in severe renal impairment (GFR < 30 mL/min). Naltrexone (a mu-opioid antagonist) reduces alcohol cravings but is contraindicated in patients with acute hepatitis, liver failure, or those requiring opioid analgesics. Disulfiram (an aldehyde dehydrogenase inhibitor) is a second-line agent that causes an unpleasant reaction (flushing, nausea, tachycardia) if alcohol is consumed; it requires high patient compliance.
Opioid Use Disorder: Maintenance options include methadone (a long-acting full mu-opioid agonist requiring daily clinic visits; monitor QTc interval), buprenorphine (a partial mu-opioid agonist, typically combined with naloxone to prevent intravenous abuse; can precipitate withdrawal if initiated before the patient is in active withdrawal), and naltrexone (available as a monthly depot injection).
Tobacco Use Disorder: Options include nicotine replacement therapy (patches, gum), varenicline (a nicotinic receptor partial agonist; most effective but monitor for neuropsychiatric side effects), and bupropion (norepinephrine-dopamine reuptake inhibitor; contraindicated in patients with seizure disorders or a history of bulimia or anorexia nervosa).
A 42-year-old man is brought to the emergency department by his brother. The patient has a history of chronic alcohol abuse and had his last drink approximately 14 hours ago. On examination, he is anxious, sweating, and has a marked bilateral hand tremor. His blood pressure is 150/95 mmHg, heart rate is 108/min, and temperature is 37.2°C (99.0°F). He is fully oriented to person, place, and time. What is the most appropriate pharmacotherapy for this patient's acute symptoms?
A 28-year-old man is brought to the emergency department by paramedics after being found unresponsive in an alley. On physical examination, his respiratory rate is 6 breaths per minute, heart rate is 54 beats per minute, and blood pressure is 98/60 mmHg. His pupils are 1 mm bilaterally and minimally reactive to light. What is the most appropriate goal for the administration of intravenous naloxone in this patient?
A 45-year-old woman seeks pharmacological treatment to help her maintain abstinence from alcohol. She has a history of alcohol use disorder and has been sober for 2 weeks. Her past medical history is significant for decompensated cirrhosis with ascites and encephalopathy. Her renal function is normal (serum creatinine 0.8 mg/dL, estimated GFR 90 mL/min). Which of the following is the most appropriate first-line medication for this patient?