Time course of panic disorder and posttraumatic stress disorder onsets.

Purpose: Posttraumatic stress disorder (PTSD) often co-occurs with panic disorder (PD), with some etiological models positing a causal role of panic reactivity in PTSD onset; however, data addressing the temporal ordering of these conditions are lacking. The aim of this study was to examine the bi-directional associations between PD and PTSD in a nationally representative, epidemiologic sample of trauma-exposed adults.
Methods: Participants were community-dwelling adults (62.6% women; M _age  = 48.9, SD 16.3) with lifetime DSM-IV PTSD criterion A trauma exposure drawn from the 2001/2 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) and re-interviewed in 2004/5 (N = 12,467). Cox discrete-time proportional hazards models with time-varying covariates were used to investigate the bi-directional associations between lifetime PD and PTSD, accounting for demographic characteristics, trauma load, and lifetime history of major depression, generalized anxiety disorder, and social anxiety disorder.
Results: PD was significantly associated with subsequent onset of PTSD (HR 1.210, 95%CI = 1.207-1.214, p < .001), and PTSD was significantly associated with onset of PD (HR 1.601, 95% CI 1.597-1.604, p < .001). The association between PTSD and subsequent PD was stronger in magnitude than that between PD and subsequent PTSD (Z = - 275.21, p < .01). Men evidenced stronger associations between PD and PTSD compared to women.
Conclusions: Results were consistent with a bidirectional pathway of risk, whereby PD significantly increased risk for the development of PTSD, and PTSD significantly increased risk for PD. Given the association between PTSD and subsequent PD, particularly among men, clinicians may consider supplementing PTSD treatment with panic-specific interventions, such as interoceptive exposure, to prevent or treat this disabling comorbidity.