Mood and Anxiety Disorders

1. THE 2-MINUTE PHYSIOLOGY (Rapid Pathophysiology)

• The Neurotransmitter & Second-Messenger Failure: Mood and anxiety disorders are not merely "chemical imbalances" of monoamines; they represent complex, systemic neurobiological failures. In depressive disorders, while serotonin and dopamine are implicated, evidence points heavily toward downstream intracellular breakdowns involving second-messenger systems like cyclic adenosine monophosphate (cAMP) and phosphatidylinositol.
• The Anxiety Matrix: Anxiety and panic disorders are driven by specific neuroanatomical disruptions:
• Serotonin: Dysregulation in the amygdala and periaqueductal gray matter.
• Dopamine: Dysfunction in the mesolimbic, mesocortical, and nigrostriatal tracts.
• Norepinephrine/Epinephrine: A hyper-adrenergic state with direct autonomic nervous system hyperactivation.
• GABA: A critical depletion of inhibitory GABAergic tone, removing the "brakes" from the CNS.
• The Medical Overlap: These identical neurotransmitter pathways are triggered by organic physiological stressors (hypoxia, hypoglycemia, sympathomimetic toxicity, and withdrawal states), which is why organic disease perfectly mimics functional psychiatric illness.

2. THE BEDSIDE ACTION PLAN (Rapid ER Management)

• Immediate Stabilization & Safety: The ED environment is highly stimulating and can rapidly escalate agitation. Immediately place the patient in a quiet area and reduce environmental stimulants (e.g., dimming the lights).
• The 1:1 Protocol: If there is any concern for suicidal ideation, immediately place the patient on 1:1 observation in a safe environment, stripped of potential weapons or hazards (including their own clothing/belongings).
• De-escalation & Chemical Support: Attempt verbal de-escalation first. If the patient remains highly anxious or agitated, offer anxiolytic medication early in the presentation to prevent escalation. Physical restraints and seclusion are an absolute last resort.
• Collateral Information: Rapidly obtain collateral history from guardians, friends, police, or EMS to establish the baseline and identify acute triggers or substance use.

3. THE DIAGNOSTIC GRID (Differential Diagnosis & Workup)

Emergency clinicians must initially evaluate all psychiatric patients as if their symptoms are resulting from organic disease.

• Critical "Can't-Miss" Differentials:
• Cardiopulmonary: Acute Coronary Syndrome (ACS), Pulmonary Embolism, Hypoxia.
• Toxicologic: Withdrawal from alcohol, benzodiazepines, opiates, or SSRI/SNRIs; Intoxication with cocaine, amphetamines, or caffeine.
• Endocrine/Metabolic: Hypoglycemia, Thyroid storm, Hypothyroidism, Electrolyte derangements.
• Neurologic: Transient Ischemic Attack (TIA), NMDA receptor encephalitis, Traumatic Brain Injury (TBI).
• Prioritized Workup:
• Level B ACEP Guideline: Routine laboratory testing of all alert, cooperative psychiatric patients is of low yield. The diagnostic evaluation should be strictly directed by the history and physical examination.
• Targeted Labs (if indicated): Point-of-care glucose, CBC, electrolytes, beta-hCG, thyroid function tests, and serum salicylate/acetaminophen levels (especially in suspected self-harm).
• Urine Toxicology: Routine urine drug screens do not generally alter ED management in alert, cooperative patients and are not routinely required.

4. THE VISUAL BOARD (ECG / POCUS / Imaging)

• Standard ECG (The Critical Differentiator): You must obtain an ECG on patients presenting with acute "panic" symptoms (chest pain, palpitations, diaphoresis, shortness of breath, feeling of impending doom) to explicitly rule out ACS and tachyarrhythmias (like SVT or prolonged QTc). 9% of patients presenting to the ED with a diagnosis of panic disorder are ultimately diagnosed with ACS.
• CT Head (Non-Contrast): Not routinely indicated for isolated mood/anxiety symptoms, but mandatory if there is a history of trauma, sudden uncharacteristic change in behavior, new-onset seizure, or focal neurologic deficit to rule out TBI or intracranial hemorrhage.

5. THE SCORING MATRIX (Risk Stratification & Guidelines)

• Organic vs. Functional Risk Predictors: Suspect an underlying medical issue driving the anxiety if the patient exhibits: onset of anxiety symptoms after 35 years of age, lack of personal/family psychiatric history, absence of significant life stress events, and a poor response to antianxiety medications.
• Self-Harm Triage Stratification:
• Level 2 (Very Urgent): Extremely agitated, aggressive, confused, or requiring restraint.
• Level 3 (Urgent): Agitated, bizarre behavior, severe depression, psychotic symptoms.
• Level 4 (Less Urgent): Symptoms of anxiety/depression without suicidal ideation.
• Pediatric Screening (HEADS-ED): A tool to assess pediatric psychiatric emergencies. A cumulative score of \(\ge\)7 or a suicide risk score of \(\ge\)2 mandates a formal psychiatric assessment by a mental health clinician.

6. THE DANGER ZONE (Pitfalls & Critical Actions)

• The "Panic Attack" Premature Closure: The most deadly cognitive trap is assuming a patient with chest pain, dyspnea, and diaphoresis is simply having a panic attack. Panic disorder in the ED is strictly a diagnosis of exclusion. You must clinically risk-stratify for ACS and Pulmonary Embolism first.
• Failure to Assess Suicide Risk: Patients with anxiety disorders have a 10-fold greater suicide risk compared to the general population, which increases further if a comorbid mood disorder is present. Board examiners mandate explicit documentation of suicide and homicide risk assessment on every patient presenting with a mood or anxiety complaint.
• Missing Organic Mimics: A physical exam and vital signs can be entirely normal in early psychiatric illness or eating disorders; however, abnormal vital signs (tachycardia, fever, hypertension) strongly suggest an organic medical cause for the anxiety and must not be ignored.

7. MCQ MASTERCLASS (Written Exam Tips)

• The High-Yield Buzzword: If a test question describes a patient with a "sudden, abrupt surge of intense fear reaching a peak within minutes" accompanied by palpitations and a feeling of choking, the classic diagnosis is a Panic Attack. However, if the patient is older than 35 with no prior history, the question is testing your ability to identify an organic medical mimic.
• The Distractor: A stem features a 45-year-old female presenting with acute chest pain, hyperventilation, and a fear of dying. She is hyperventilating in triage. The distractor options will be "Administer Lorazepam" or "Provide a paper bag to breathe into."
• The Correct Answer: The correct answer will always be the medical screening action first—"Obtain an immediate 12-lead ECG" or "Check a point-of-care blood glucose".

8. THE BOARDROOM SCRIPT (OSCE & Oral Board Tips)

• The Opening Salvo: "Examiner, this patient presents with an acute mood/anxiety complaint. My immediate priority is to ensure the safety of the patient and my staff. I am placing the patient in a quiet room with decreased stimulation. I will concurrently evaluate this patient as if their symptoms are resulting from a life-threatening organic disease."
• The Medical Rule-Out: "To rule out medical mimics, I am immediately obtaining a full set of vital signs, a point-of-care blood glucose, and a 12-lead ECG. I am actively screening for signs of acute coronary syndrome, pulmonary embolism, hypoxia, and toxicologic withdrawal."
• The Handoff: "With organic life-threats ruled out, my physical exam and labs are reassuring. I have formally assessed the patient for suicidal and homicidal ideation and placed them on 1:1 observation. I am now consulting the psychiatric liaison service for a comprehensive psychosocial assessment and disposition planning."