Antidepressants may speed up memory loss in dementia patients
Those newly diagnosed with dementia suffered a faster decline in their brain function if they were taking a common antidepressant, a Swedish study suggests.
Taking antidepressants could speed up memory loss in older adults with dementia, a large study has suggested.
Researchers found that people taking selective serotonin reuptake inhibitors (SSRIs), the most common type of antidepressant, suffered a faster decline in their brain function.
A team at the Karolinska Institute in Sweden looked at 18,700 adults, who were aged 78 on average and had all been newly diagnosed with dementia.
They were followed for the next decade, during which period nearly one in four patients were put on antidepressants, and this was compared with the results of regular memory tests. Those who took SSRI drugs experienced a faster decline in their brain function, measured by a clinical test called the mini-mental state examination, which measures the ability to recall information including the date, year and lists of words. On average the score, measured out of 30, decreased by an extra 0.42 points per year in those on antidepressants.
Patients on antidepressants were also more likely to suffer fractures and to die of any cause.
Antidepressants are widely prescribed for people with dementia who become agitated or develop changes in mood and behaviour.
Nearly nine million people in England take antidepressants, the latest NHS data shows, and more than half of these are on SSRIs, such as sertraline and citalopram. The drugs are the first choice of medicine for anxiety and depression on the NHS.
Writing in the journal BMC Medicine, the researchers said that “antidepressants were associated with increased cognitive decline” but that the study could not prove cause and effect as it could be that depression itself sped up memory loss, rather than the drugs.
Sara Garcia-Ptacek, the study’s author, said: “Depressive symptoms can both worsen cognitive decline and impair quality of life, so it is important to treat them. Our results can help doctors and other healthcare professionals choose antidepressants that are better adapted for patients with dementia.”
Nearly one million people in the UK have dementia and researchers have called for greater research into finding the most suitable antidepressants for patients.
Richard Oakley, of the 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.
“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.”
Professor Tara Spires-Jones, group leader in the UK Dementia Research Institute, said: “People who needed antidepressants may have had more aggressive disease or the depression itself could have been affecting disease progression. Previous studies have also reported mixed results, highlighting the need for more research before we have a full understanding of the effects of antidepressant use on dementia progression.”
Prasad Nishtala, a reader at the University of Bath, said: “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.”
The Times
