PTSD Combined With Some Medications Dramatically Increases Dementia Risk

SNRIs and Benzodiazepines Have Greatest Effect

By Annette M. Boyle

IOWA CITY, IA—Post-traumatic stress disorder (PTSD) appears to increase the risk of dementia in veterans but exactly why remains unclear: Is the increased risk attributable to frequent comorbidities such as diabetes and traumatic brain injury or to medications used to treat PTSD or to other factors?

Research by investigators at the Iowa City VA Health System confirmed some expected associations—and turned up some surprising connections between common medications and elevated dementia risk, even in patients without PTSD.

The study, published in the Journal of the American Geriatrics Society, “went a step beyond prior research that has found an association between PTSD and the onset of dementia,” explained co-author Thad Abrams, MD, MS, of the Iowa City VA Health System and the University of Iowa. “Our study confirmed that association, with findings that were similar in both direction and magnitude.”1

The study tracked 417,172 veterans over age 55 who received care through the VA for nine years and had at least one clinical encounter every two years from 2004-2012. At the start, 5.4% of the veterans had a diagnosis of PTSD and none had a diagnosis of dementia or cognitive impairment.

Previous studies found that PTSD increased the risk of dementia by 52%-77%. Depending on the adjustments made, the Iowa City study showed a comparable correlation, with PTSD doubling the risk of dementia diagnosis over nine years in an unadjusted analysis and increasing it by 36% when adjusted for medical and psychiatric comorbidities, demographics and clinic utilization.

Examining the impact of various medications provided insights not detected in previous studies. The team “noted several interactions between PTSD and various medication on the association with dementia,” Abrams told U.S. Medicine. Overall, veterans with PTSD who took none of the antidepressants or antipsychotics commonly prescribed for the condition had a 55% higher risk of dementia than those who had neither PTSD nor took those any of those medications.

The study found that patients with PTSD who have received selective serotonin reuptake inhibitors (SSRIs), newer antidepressants and atypical antipsychotics had a substantially increased risk of dementia compared to PTSD patients who were not prescribed those three classes of medications and to patients without PTSD who do not use those classes of medications. The results “suggest that the associations between PTSD diagnosis and the risk of dementia diagnosis varies significantly according to receipt of these medication classes,” the authors said.

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Some of the drugs had a stronger association with dementia. “The associations between dementia and SSRIs were effect-modified by presence of PTSD,” Abrams said. Veterans with PTSD who had not been prescribed SSRIs had a 55% increased risk of dementia compared to veterans without PTSD who did not take SSRIs, but veterans with PTSD who had been prescribed SSRIs had twice the risk of dementia compared to veterans without PTSD who had not been prescribed SSRIs. A similar association was found with novel antidepressants.

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