The purpose of this study is to investigate the etiology of panic disorder. Specific objectives include comparing and contrasting the genetic versus environmental factors that contribute to the etiology of panic disorder. Currently, there are four main theories to explain the etiology of panic disorder: psychodynamic, behavioral, cognitive, and biological.

Methodology: This is accomplished via a systematic review of evidence-based medicine. Search engines utilized included: MEDLINE FirstSearch, Medline PubMed, ProQuest Nursing, PsycINFO, Current Research and a bibliographic search of selected articles.

Results: The best quality evidence indicates that between 40-60% of the etiology of panic disorder is due to genetics. Further, a body of good quality research states that environmental influences to the expression of panic disorder; such as CO2 reactivity, learned anxiety, and fear conditioning; may also be hereditable traits. Lifestyle choices, such as smoking, also play a role in the etiology of panic disorder. The evidence-based review does not support a role for the psychodynamic theory in the etiology of panic disorder.

Conclusion: The majority of panic disorder is due to genetics. The minority of panic disorder etiology is best explained by the cognitive and behavioral theories on environmental factors. Such data suggest the best treatment for panic disorder patients should focus on medical therapy and cognitive-behavioral therapy.