Kuopio, Finland—Antidepressant use was previously found to increase the likelihood that Alzheimer’s disease patients will fall and fracture their hips. Now, a new study extends that risk to head injuries and even to traumatic brain injury.

The report, published in Alzheimer’s Research & Therapy, notes that the risk of head injuries with antidepressant use appeared to be highest during the first 30 days of use but persisted up to 2 years.

University of Eastern Finland researchers point out that the link was also confirmed in a study design comparing time periods within the same person, thereby eliminating selective factors. They also emphasize that the use of other psychotropic drugs did not account for the increased risk.

The study says that the association with traumatic brain injuries was not as strong as for head injuries, possibly because fewer of those events occurred in the study population.

The research was part of the nationwide register-based MEDALZ study, which included all community-dwelling persons diagnosed with Alzheimer’s disease in Finland during 2005-2011. The study included 10,910 antidepressant users and 21,820 nonusers, all of whom had Alzheimer’s disease.

Results indicate that the age-adjusted event rate per 100 person-years of increased risk of head injuries with antidepressant use was 2.98 during use and 2.43 during nonuse, for an adjusted hazard ratio (HR) of 1.35.

For traumatic brain injuries, the age-adjusted event rate per 100 person-years was 1.33 during use and 1.10 during nonuse, for an adjusted HR of 1.26.

The study notes that the risk was highest during the first 30 days of use (HR 1.71) for head injuries and traumatic brain injuries (HR 2.06).  The risk remained elevated for head injuries for over 2 years of use, study authors add.

Senior Researcher Heidi Taipale, PhD, said, “Our findings give cause for concern because persons with Alzheimer’s disease frequently use antidepressants, which have been considered a safer alternative to, for example, benzodiazepines.”

“Our study population consisted of persons diagnosed with Alzheimer’s disease, but it is likely that the risk is similar also in other older persons without Alzheimer’s disease. This is something we will be studying in the future,” Taipale added.

“Antidepressant use was associated with an increased risk of the most severe outcomes, head and brain injuries, in persons with Alzheimer’s disease,” the study authors conclude. “Antidepressant use should be carefully considered and the association confirmed in future studies.”

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