A new study, published in the Journal of the American Geriatrics Society, investigates the association between a diagnosis of posttraumatic stress disorder (PTSD), psychiatric medication, and developing dementia in older US veterans. The results of the retrospective cohort study suggest that some psychiatric drugs are associated with later onset of dementia for veterans with PTSD. The researchers, led by Francis Mawanda from the University of Iowa College of Public Health, write:
“We found statistically significant interactions between PTSD diagnosis and the use of SSRI [selective serotonin reuptake inhibitors], NA [novel antidepressants], and AA [atypical antipsychotics] on the risk of dementia diagnosis, suggesting that the associations between PTSD diagnosis and the risk of dementia diagnosis varies significantly according to receipt of these medication classes.”
Recent research has suggested an association between PTSD and dementia in older adults. However, the authors note that “prior research failed to consider the potential impact of psychotropic medication use commonly encountered with a diagnosis of PTSD among US veterans.”
Research shows mixed findings on the impact of SSRIs and SNRIs on cognitive functioning. Studies have shown that long-term use of benzodiazepines is linked to an increased risk of dementia. And atypical antipsychotics have been associated with poorer cognitive functioning in people who have been diagnosed with dementia. This is especially concerning given recent research showing that veterans with PTSD are more likely to be prescribed antipsychotics if they also have dementia.
The authors state, “the purpose of this study was to determine the impact of psychotropic medication use on the association between PTSD and the risk for dementia in a nationally representative sample of US veterans aged 56 years and older.” The researchers analyzed 2003-2012 data from 417,172 veterans using Veteran Health Administration databases.
Almost all the veterans (98%) were male, and most (82%) were White. At the beginning of the data collection period, 5.4% of veterans were diagnosed with PTSD. Over the nine-year follow-up period, 6.2% of veterans were diagnosed with dementia. The authors find that having a PTSD diagnosis significantly increases older veteran’s risk of developing dementia. The authors report:
“Patients diagnosed with PTSD and using SSRI [selective serotonin reuptake inhibitors], NA [novel antidepressants], or AA [atypical antipsychotics] are significantly more likely to be diagnosed with dementia compared to both those with and without a PTSD diagnosis and not using any psychotropic medications.”
The researchers also find, “SNRI [serotonin-norepinephrine reuptake inhibitors] and BZA [benzodiazepines] were associated with significant independent effects on the risk for dementia diagnosis suggesting that SNRI or BZA might be associated with an increased risk of dementia diagnosis regardless of PTSD diagnosis.”
The results of this large-scale study provide insight into the association between PTSD and dementia, and especially the potential impact of psychiatric medication on the risk of developing dementia in individuals diagnosed with PTSD. The authors note alternative explanations for their findings, including that psychotropic medication may impact dementia independent of a PTSD diagnosis, or that underlying psychiatric disorders, rather than the drugs, are the primary risk factor for developing dementia. The researchers also emphasize that these findings should not be generalized outside the veteran population. Therefore, the authors call for more research to investigate further the effect that psychiatric medication may have on the risk of developing dementia in individuals with PTSD.
Mawanda, F., Wallace, R. B., McCoy, K., & Abrams, T. E. (2017). PTSD, psychotropic medication use, and the risk of dementia among US veterans: A retrospective cohort study. Journal of the American Geriatrics Society. Advance online publication. doi:10.1111/jgs.14756 (Abstract)