Risk of Epilepsy in Individuals With Posttraumatic Stress Disorder: A Nationwide Longitudinal Study

OBJECTIVE Several cross-sectional studies have reported a relationship between posttraumatic stress disorder (PTSD) and epilepsy. However, the temporal association between PTSD and epilepsy has rarely been investigated. We hypothesized that the risk of developing epilepsy later in life would be higher in patients with PTSD than in those without PTSD. METHODS Using the Taiwan National Health Insurance Research Database, 6425 individuals with PTSD and 24,980 age-/sex-matched controls were enrolled between 2002 and 2009 in our study and followed up to the end of 2011. Those who developed epilepsy during the follow-up period were identified. RESULTS Individuals with PTSD had a higher incidence of developing epilepsy (2.65 versus 0.33 per 1000 person-years, p < .001), with an earlier onset of epilepsy (37.53 years [15.80 years] versus 48.11 years [23.97 years], p = .002) than did the controls. Individuals with PTSD had an elevated risk of developing epilepsy (hazard ratio [HR] = 3.72, 95% confidence interval [CI] = 2.27-6.11) during the follow-up after adjustment for demographic data and medical and psychiatric comorbidities. Sensitivity analyses after excluding the observation in the first year (HR = 2.53, 95% CI = 1.44-4.47) and the first 3 years (HR = 2.14, 95% CI = 1.15-4.01) revealed consistent results. CONCLUSIONS These results supported a temporal association between PTSD and the development of epilepsy. Further studies are warranted to investigate the underlying pathophysiological pathways that explain the longitudinal association of PTSD with subsequent epilepsy.