Drugs for PTSD linked to increased risk of dementia

Certain psychotropic drugs used to treat post-traumatic stress disorder (PTSD) increase the risk of developing dementia, including in patients who do not have PTSD but take the drugs for other conditions, study results published in the Journal of the American Geriatrics Society
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show (online, May 2017).

Previous research has shown that PTSD is a significant risk factor for developing dementia, so researchers set out to determine whether specific treatments for PTSD could impact on that risk.

The study involved 3,139,780 veterans aged 56 and older, 5.4% of whom had been diagnosed with PTSD. Participants were followed up for nine years, during which time 25,639 (6.2%) veterans received a dementia diagnosis. The researchers looked at the how the use of psychotropic medicines impacted on the risk of developing dementia.

As expected, a diagnosis of PTSD was found to significantly increase the risk of a dementia diagnosis. The hazard ratio for dementia diagnosis among veterans diagnosed with PTSD and not using psychotropic medications was 1.55 (95% confidence interval [CI] 1.45–1.67). However, the results show that the use of selective serotonin reuptake inhibitors, novel antidepressants and atypical antipsychotics increased that risk of dementia still further with the drugs associated with hazard ratios for dementia of 1.99 (95% CI 1.72–2.29), 2.02 (95% CI 1.78–2.30) and 4.21 (95% CI 3.72–4.76) respectively. Veterans who did not have PTSD and took the drugs also had an increased risk of dementia.

While the use of serotonin-norepinephrine reuptake inhibitors (SNRI) or benzodiazepines (BZA) to treat PTSD was not found to significantly increase the risk of dementia specifically in patients with PTSD, the results showed that use of either drug was found to be independently associated with an increased risk of dementia diagnosis in the veterans, regardless of PTSD diagnosis.

The researchers say that further research was needed “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”.