Researchers suggest that medications used to treat PTSD may influence how the disorder impacts dementia risk.
Researchers from the University of Iowa came to their conclusions by analyzing the data of more than 3 million veterans.
They found that veterans with post-traumatic stress disorder (PTSD) were at much higher risk of developing dementia than those without the condition, but that the risk varied depending on the medications they were using.
Study co-author Dr. Thad Abrams, of the Department of Epidemiology at Iowa, and colleagues recently reported their findings in the Journal of the American Geriatrics Society.
PTSD is a mental health condition triggered by witnessing or experiencing a traumatic event.
According to the United States Department of Veterans Affairs, around 7 to 8 percent of people in the U.S. will experience PTSD at some point in their lives.
The condition is more common among people in the military, who have greater exposure to traumatic and life-threatening experiences. Statistics suggest that around 15 percent of veterans who served in the Vietnam War were diagnosed with PTSD, while around 12 percent of Gulf War veterans have the condition in any given year.
Previous studies have suggested that individuals with PTSD may be at greater risk of cognitive decline and dementia. For their study, Dr. Abrams and colleagues set out to explore this further, as well as to investigate how medications used to treat PTSD might impact dementia risk.
Psychoactive medications may influence how PTSD affects dementia risk
To reach their findings, the researchers reviewed the health data of 3,139,780 U.S. veterans with an average age of 68 years, including 417,172 in their final analysis.
At study baseline in 2002-2003, a total of 22,674 participants had a diagnosis of PTSD, but all subjects were free of cognitive impairment and dementia.
Over 9 years of follow-up, 25,639 of the participants received a dementia diagnosis.
Overall, among veterans who were not using any medications at study baseline, those with PTSD were much more likely to develop dementia during follow-up.
However, the use of certain medications appeared to influence the risk of dementia significantly.
Veterans with PTSD who used selective serotonin reuptake inhibitors, novel antidepressants, and atypical antipsychotics were found to have a greater dementia risk than those with and without PTSD who were not taking these medications.
Furthermore, the researchers found that the use of serotonin-norepinephrine reuptake inhibitors, benzodiazepine, and novel antidepressants was associated with an increased risk of dementia, independent of a PTSD diagnosis.
Commenting on what their findings show, the researchers say:
"PTSD diagnosis is associated with an increased risk for dementia diagnosis that varied with receipt of psychotropic medications."
Based on their findings, the researchers say that it is possible that psychoactive medications might influence how PTSD influences an individual's risk of developing dementia, though they note that further studies are needed to determine whether this is the case.
"Although our results showed significant independent and effect modifying impacts, the association between psychotropic medication use and the risk of dementia remains an area for further inquiry," say the authors.
"Thus, we recommend further research accounting for dosage, duration, and indications for use to determine whether the independent and the effect modifying impacts of psychotropic medication use on the risk for dementia are due to differences in PTSD severity and symptomatology, other psychiatric comorbidity, or whether they represent independent and direct effects on dementia neuropathogenesis."