Dementia patients who took antidepressants saw faster declines in thinking ability as the Alzheimer’s Society demands regular medication reviews for patients
Dementia patients who took a common form of antidepressants saw faster declines in thinking ability, a study has shown.
The Alzheimer’s Society has called for regular medication reviews for patients amid concerns antidepressants could be wrongly prescribed for to tackle symptoms caused by dementia. An 11-year study of 18,740 dementia patients in Sweden found prescriptions of selective serotonin reuptake inhibitors (SSRIs) were linked with more rapid decline. However some researchers say this may be due to patients with more severe dementia being more likely to be prescribed the antidepressants.
Dr Richard Oakley, director at Alzheimer’s Society, said: “This study suggested that antidepressants led to faster rates of memory and thinking decline in people with dementia. But it did not rule out the possibility that the changes were due to the presence of depression rather than antidepressant use, so further research is needed to understand the effects of antidepressants.
“Alzheimer’s Society wants to see the severity of an individual’s dementia recorded on their primary care records as either mild, moderate or severe. This is especially important as the study shows a decline in memory and thinking skills was stronger in people with more severe dementia who took antidepressants than those who didn’t. It’s vital that regular reviews are carried out when prescribing antidepressants, but recent research showed that less than half of people with a dementia diagnosis had their medication reviewed in the preceding 12 months.”
The study by the Karolinska Institutet in Sweden enrolled newly diagnosed dementia patients with an average age of 78 between 2007 and 2018. They were prescribed first-time antidepressants up to six months before dementia diagnosis.
Cognitive function was measured via the Mini-Mental State Examination (MMSE) score looking at orientation and short-term memory. During a follow-up period of four years some 23% of patients received a new prescription for an antidepressant. SSRIs were the most commonly prescribed form, accounting for 64.8% of all antidepressant prescriptions.
Higher doses of SSRIs were associated with a higher risk for severe dementia, defined as a more pronounced decline in a patient’s MMSE score.
Dr Prasad Nishtala, reader at the University of Bath, said: “This large population-level study from Sweden uses real-world data and is well-conducted. However there are some important limitations that should be considered. One major issue is that the severity of depression in dementia patients wasn’t fully accounted for, which has the potential to bias the results. Additionally, there may be a ‘channelling bias’ meaning that certain antidepressants like citalopram and sertraline might have been more commonly prescribed to patients with severe dementia, which could also bias the results.
“This study suggests that SSRIs like citalopram and sertraline might also speed up cognitive decline. However, it doesn’t explain how or why this happens at a biological level. Because of these limitations, the study’s findings should be interpreted with caution and ideally replicated using other real-world data sources.”
The findings are published in the journal BMC Medicine.