Posttraumatic Stress Disorder, Antipsychotic Use and Risk of Dementia in Veterans

OBJECTIVES: To examine the risk of dementia associated with posttraumatic stress disorder (PTSD) and the contribution of antipsychotic use to this risk. DESIGN: Retrospective cohort study SETTING: Australia. Administrative claims data from the Australian Government Department of Veterans' Affairs were used. PARTICIPANTS: Male Vietnam veterans aged 55 to 65 at baseline (2001-02) with no preexisting dementia diagnosis (N = 15,612). MEASUREMENTS: The association between PTSD and dementia was assessed over 12 years of follow-up. Dementia was identified as a hospital diagnosis, dementia record in service disability data, or dispensing of medicines for dementia. Cox-proportional hazards models were used, with age as the time-scale. Results were stratified according to baseline antipsychotic use. RESULTS: No greater risk of dementia was observed with PTSD. In veterans who received antipsychotics, dementia risk was significantly higher than in those who did not (hazard ratio (HR) = 2.1, 95% confidence interval (CI) = 1.4-3.3). Dementia risk was significantly greater in veterans hospitalized for PTSD who received antipsychotics (HR = 2.2, 95% CI = 1.1-4.6) and veterans without PTSD who received antipsychotics (HR = 4.3, 95% CI = 2.1-8.6) than in those without PTSD with no antipsychotic use. CONCLUSION: Antipsychotic use may be a contributor to dementia risk. These findings should be interpreted with caution because the study design was observational. Further research using prospective study designs in settings where diagnostic data, cognitive function, and disease severity are available are required.