Risk for developing dementia among patients with posttraumatic stress disorder: A nationwide longitudinal study

Objectives Previous studies suggested a relationship between posttraumatic stress disorder (PTSD) in the specific population (i.e., war survivors and veterans) and subsequent dementia risk. However, whether patients with PTSD in the general population were at an increased risk for developing dementia in later life remained unclear. Methods The Cox regression analysis was performed using data from the Taiwan National Health Insurance Research Database. The study sample comprised 1750 patients diagnosed with PTSD between 2001 and 2009 and 7000 age-/sex-matched individuals without PTSD. Those who developed dementia during follow-up to the end of 2011 were identified. Results After adjusting for demographic data and medical and psychiatric comorbidities, PTSD was an independent risk factor for the risk for subsequent dementia (hazard ratio [HR]=4.37; 95% confidence interval [CI]: 2.53–7.55). There was a dose-dependent relationship between PTSD severity indicated by the frequency of psychiatric clinics visiting of PTSD (times per year) and the risk of subsequent dementia (<5: HR: 2.81, 95% CI: 1.50–5.29; 5–10: 6.90, 95% CI: 3.09–15.40;>10: HR: 18.13, 95% CI: 9.13–36.00). Furthermore, patients with depressive disorder and medical comorbidities, such as cerebrovascular diseases, diabetes mellitus, and head injuries, exhibited a higher risk for developing dementia. Discussions Our study suggested a significant dose-dependent association between PTSD and its severity and an increased risk of developing dementia later in life. The importance of mental care for trauma victims would increase in the coming century, and our findings broadened another era for the end result of a widely prevalent psychiatric disorder.