Anxiety disorder differential diagnosis

DDx Overview - The Anxiety Spectrum

• Generalized Anxiety Disorder (GAD): Chronic, excessive worry about various topics for ≥ 6 months.
• Panic Disorder: Recurrent, unexpected panic attacks with persistent fear of having more.
• Agoraphobia: Intense fear of ≥ 2 situations where escape may be difficult.
• Social Anxiety Disorder: Marked fear of social situations and potential scrutiny.
• Specific Phobia: Overwhelming fear of a single object or situation, leading to avoidance.

⭐ Panic disorder and agoraphobia are distinct diagnoses; many patients with agoraphobia do not have panic disorder.

Panic Disorder vs. GAD - Sudden vs. Steady

⭐ Exam Pearl: The worry in Panic Disorder is focused on the panic attack itself (fear of the fear), while GAD worry is "free-floating" and attaches to numerous everyday stressors.

Social Anxiety vs. Agoraphobia - Fear of Crowds or Critics?

• Social Anxiety Disorder (SAD): Fear of scrutiny & negative judgment.
  • Triggers: Performance or social situations (e.g., public speaking, parties).
  • Core thought: "They will think I'm stupid/awkward."
• Agoraphobia: Fear of situations where escape may be difficult if panic occurs.
  • Triggers: Crowds, public transport, open spaces, being outside home alone.
  • Core thought: "I'll be trapped and unable to get help."

⭐ Diagnostic Pearl: A person with agoraphobia might feel safe in a crowd with a trusted companion, whereas someone with SAD fears the scrutiny regardless of company.

OCD & PTSD - Intrusions & Trauma

• Obsessive-Compulsive Disorder (OCD)

  • Intrusive thoughts (obsessions) are ego-dystonic; internally generated fears unrelated to a past trauma.
  • Compulsions are repetitive acts aimed at neutralizing anxiety or preventing a dreaded event.

• Post-Traumatic Stress Disorder (PTSD)

  • Intrusions are re-experiencing a specific, past traumatic event (e.g., flashbacks, nightmares).
  • Characterized by persistent avoidance of stimuli associated with the trauma.

⭐ Exam Tip: The core distinction lies in the content of the intrusion. OCD fears are often irrational and not based on a real past event, whereas PTSD intrusions are a direct reliving of a real, historical trauma.

Medical Mimics - It's Not All in the Head

• Endocrine: Hyperthyroidism, pheochromocytoma, hypoglycemia, Cushing's syndrome.
• Cardiopulmonary: Myocardial infarction, pulmonary embolism, arrhythmias (e.g., SVT), asthma/COPD.
• Neurologic: Seizure disorders (especially temporal lobe), vestibular dysfunction, neoplasms.
• Substance-Related: Caffeine intoxication, stimulant use (cocaine, amphetamines), alcohol/sedative withdrawal, medication side effects (steroids, bronchodilators).

⭐ Always consider pheochromocytoma in patients with episodic anxiety, headaches, diaphoresis, and treatment-resistant hypertension.

High‑Yield Points - ⚡ Biggest Takeaways

• Panic disorder involves recurrent, unexpected attacks; agoraphobia is fear of situations where escape is difficult.
• GAD is excessive, multi-topic worry for >6 months, distinguishing it from normal anxiety.
• Social anxiety centers on fear of scrutiny, while agoraphobia focuses on inescapable situations.
• OCD is ego-dystonic (distressing), whereas OCPD is ego-syntonic (part of self-identity).
• Symptom duration distinguishes PTSD (>1 month) from acute stress disorder (<1 month).
• Rule out medical causes like hyperthyroidism, pheochromocytoma, and caffeine/stimulant use.