Panic Disorder

Panic disorder is a condition where there are recurrent unexpected panic attacks, in the absence of triggers. It is marked by persistent concern about additional panic attacks and/or maladaptive change in behaviour related to the attacks.

The lifetime prevalence of panic disorder is 2.5%, and it affects 3 females for every 1 male. Panic disorder is more prevalent in patients with medical conditions, including thyroid disease, cancer, chronic pain, cardiac disease, irritable bowel syndrome, migraine, as well as allergic and respiratory diseases compared with the general population.

A panic attack is a single, discrete episode of intense fear and discomfort. A panic attack must peak abruptly (rapid onset of under 10 minutes), and must be accompanied by a cluster of physical symptoms. A typical panic attack is relatively short and lasts no more than 15 minutes. The prevalence of panic attacks (not disorder) is 11.2% in adults, and can occur in the context of anxiety disorders, other mental disorders, and medical conditions.

Criterion A

Recurrent unexpected panic attacks. A panic attack is an abrupt surge of intense fear or intense discomfort that reaches a peak within minutes, and during which time at least 4 of the following symptoms occur (Note: The abrupt surge can occur from a calm state or an anxious state):

  1. Sweating
  2. Trembling or shaking
  3. Unsteady, dizziness, light-headed, or faint
  4. Derealization (feelings of unreality) or depersonalization (being detached from one self)
  5. Excessive/accelerated heart rate, palpitations, or pounding heart
  6. Nausea or abdominal distress
  7. Tingling, numbness, parathesesias
  8. Shortness of breath
  9. Fear of losing control or “going crazy”
  10. Fear of dying
  11. Choking feelings
  12. Chest pain or discomfort
  13. Chills or heat sensations
Note: Culture-specific symptoms (e.g. - tinnitus, neck soreness, headache, uncontrollable screaming or crying) may be seen. Such symptoms should not count as one of the four required symptoms.
Criterion B

At least 1 of the attacks has been followed by at least 1 month of at least 1 of the following:

  1. Persistent concern or worry about additional panic attacks or their consequences (e.g. - losing control, having a heart attack, “going crazy”).
  2. A significant maladaptive change in behavior-related to the attacks (e.g. - behaviors designed to avoid having panic attacks, such as avoidance of exercise or unfamiliar situations).
Criterion C

The disturbance is not attributable to the physiological effects of a substance (e.g. - a drug of abuse, a medication) or another medical condition (e.g. - hyperthyroidism, cardiopulmonary disorders).

Criterion D

The disturbance is not better explained by another mental disorder:


The mnemonic STUDENTS FEAR the 3 C's can be used to remember the panic disorder criteria:

  • S - Sweating
  • T - Trembling
  • U - Unsteadiness, dizziness
  • D - Depersonalization, derealization
  • E - Excessive heart rate, palpitations
  • N - Nausea
  • T - Tingling
  • S - Shortness of breath
  • FEAR of dying
  • FEAR of losing control
  • FEAR of going crazy
  • C - Chest pain
  • C - Chills
  • C - Choking

Asking 'Do you experience panic attacks?' is too vague!

A 'panic attack' means different things to different people, and they may not actually be experiencing panic attacks. It is more important to explore whether a cluster of physical symptoms occurs and the chronology of the symptoms. It is also helpful to identify if there are specific triggers that lead to symptoms.

A true panic attack occurs only during a discrete period of time, must peak abruptly, and is accompanied by physical symptoms. Chronic anxiety on the other hand fluctuates over a period of hours to days.
  • Thyroid disease (hyperthyroidism, hypothyroidism, thyroiditis)
    • A TSH level should be always be ordered
  • Cardiovascular
    • Cardiac arrythmias (e.g. - atrial fibrillation, flutter, palpitations, dyspnea, syncope)
    • Pulmonary embolism (order D-dimer assay to exclude)
    • Acute Coronary Syndrome or Myocardial Infection[1]
      • This is especially important for women, who commonly present with atypical features compared with men
    • Electrocardiography (ECG) to assess for signs of ventricular preexcitation (short PR and delta wave), for short or long QT interval in patients with palpitations, and for ischemia, infarction, or pericarditis patterns in patients with chest pain.
  • Endocrine
    • Cushing disease, diabetes mellitus (check for hypoglycemia), parathyroid disease (hyperparathyroidism, pseudo-hyperparathyroidism), pancreatic tumours, and pituitary disease
  • Pheochromocytoma, rarely, this should be considered on the differential. Especially if the patient is not responding to conventional treatments[2][3]
    • The classic triad of pheochromocytoma symptoms includes headache, excessive sweating, and palpitations. Around 15%-20% of patients with a pheochromocytoma patients may be normotensive.
    • Plasma metanephrines (95% sensitivity), 24-hour urinary metanephrines (99% sensitivity), MRI (100% sensitivity, pheochromocytomas demonstrate a distinctive appearance), scintigraphy, and abdominal CT.[4]
  • TSH, glucose as baseline if not already done

The following treatment recommendations are based on the 2014 Canadian Clinical Practice Guidelines for anxiety, posttraumatic stress and obsessive-compulsive disorders.[5] Generally, a combination of psychotherapy and pharmacotherapy with antidepressants is superior to CBT or pharmacotherapy alone during the acute treatment phase for panic disorder.[6]

It is often helpful to explain to patients that having panic disorder is like having a car with an oversensitive alarm system: every car has an alarm system that activates when a window is smashed, but sometimes the alarm system can be hypersensitive, and even a small bump or breeze can activate it.

Cognitive Behavioural Therapy (CBT) has been extensively studied and is very efficacious in the treatment for panic disorder. In fact, CBT has been shown to be significantly more effective than pharmacological treatment in several meta-analyses.[7]

Pharmacotherapy for panic disorder

1st line Citalopram, escitalopram,[8] fluoxetine, fluvoxamine, paroxetine, paroxetine CR, sertraline, venlafaxine XR
2nd line Alprazolam, clomipramine, clonazepam, diazepam, imipramine,[9] lorazepam, mirtazapine, reboxetine
3rd line Bupropion SR, divalproex, duloxetine, gabapentin, levetiracetam, milnacipran, moclobemide, olanzapine, phenelzine, quetiapine, risperidone, tranylcypromine
Adjunctive therapy Second-line: alprazolam ODT, clonazepam
Third-line: aripiprazole, divalproex, olanzapine, pindolol, risperidone
Not recommended Buspirone, propranolol, tiagabine, trazodone