Panic disorder is an anxiety disorder characterized by recurrent unexpected panic attacks - sudden, discrete episodes of intense fear or discomfort that peak within 10 minutes (often less than a minute) and involve abrupt physical and cognitive symptoms creating a feeling of impending doom, loss of control, or death. Lifetime prevalence is approximately 2-3% with female predominance (2:1) and bimodal age distribution (peak 15-24 and 45-54 years). Pathophysiology involves dysregulation of the fear circuit (amygdala, hippocampus, brainstem), serotonergic and noradrenergic systems, GABA receptor function, respiratory control (sensitivity to CO2), interoceptive sensitivity (heightened awareness of bodily sensations), and genetic vulnerability (heritability ~40%). Approximately 50% of patients with panic disorder develop agoraphobia (fear and avoidance of situations from which escape might be difficult or embarrassing).
Panic attack symptoms (DSM-5-TR requires >=4 of 13): palpitations, pounding heart, or accelerated heart rate; sweating; trembling or shaking; sensations of shortness of breath or smothering; feelings of choking; chest pain or discomfort; nausea or abdominal distress; feeling dizzy, unsteady, lightheaded, or faint; chills or heat sensations; paresthesias (numbness or tingling); derealization or depersonalization; fear of losing control or going crazy; fear of dying. Panic disorder diagnostic criteria require recurrent unexpected panic attacks PLUS at least one month of >=1 of: persistent concern/worry about additional panic attacks or their consequences (losing control, having a heart attack, going crazy); significant maladaptive change in behavior related to attacks (avoidance of unfamiliar situations, exercise, etc.); not attributable to substances or another medical condition; not better explained by another mental disorder.
Treatment is multimodal: first-line pharmacotherapy includes SSRIs (sertraline 50-200 mg, paroxetine 20-50 mg, escitalopram 10-20 mg, fluoxetine 20-80 mg) with response in 6-8 weeks and continuation for 6-12 months minimum; SNRIs (venlafaxine XR 75-225 mg) also first-line; tricyclic antidepressants (clomipramine, imipramine) effective but with more side effects; benzodiazepines (alprazolam 1-4 mg/day, clonazepam 0.5-2 mg/day) provide rapid relief in acute presentations but reserved for short-term use due to dependence and rebound risk. Cognitive behavioral therapy (CBT) is highly effective with components: psychoeducation about panic and the fight-or-flight response, cognitive restructuring (identifying and challenging catastrophic interpretations of bodily sensations), interoceptive exposure (deliberate provocation of feared physical sensations through hyperventilation, spinning, breath holding), in vivo exposure to avoided situations, and breathing retraining. Agoraphobia management requires graded in vivo exposure with self-monitoring. Comorbid depression (50%), substance use disorders (especially alcohol used to self-medicate), and other anxiety disorders require integrated treatment. Untreated panic disorder is associated with significant impairment, increased suicide risk, and progression to chronic disability.