Media release
From: Springer NatureHealth: Some antidepressant classes may accelerate cognitive decline in patients with dementia
Prescriptions of selective serotonin reuptake inhibitors (SSRIs) — a class of antidepressants — are associated with faster rates of cognitive decline in patients with dementia, according to research published in BMC Medicine. The authors suggest that their findings, from a Swedish national cohort study, highlight a need for further research to evaluate risk differences between different antidepressant classes in patients with dementia.
Antidepressants such as SSRIs and serotonin norepinephrine reuptake inhibitors (SNRIs) are often prescribed to those with dementia on their initial diagnosis. Previous studies of antidepressant use and cognitive decline in people with dementia have been inconsistent, with some studies suggesting certain antidepressant classes — including SSRIs — have a beneficial impact on biomarkers associated with neurodegenerative diseases. However, some patients with dementia are prescribed antidepressants for depressive symptoms that may actually be behavioural and psychological symptoms of dementia. In these cases, antidepressants may be less beneficial to patients because they would not be treating the underlying cause of these symptoms.
Sara Garcia-Ptacek and colleagues conducted a population-based cohort study in Sweden between 2007 and 2018, monitoring antidepressant exposure among a cohort of 18,740 patients with a mean age of 78. The study cohort were newly diagnosed patients with dementia prescribed first-time antidepressants up to six months before dementia diagnosis. Each patient’s cognitive function was recorded through Mini-Mental State Examination (MMSE) scoring, which measures a patient’s cognitive function based on their orientation and short-term memory. During follow-up, which on average took place 4.3 years after study enrolment, 22.8% of patients received a new prescription for an antidepressant. SSRIs were the most commonly prescribed antidepressants among the cohort studied, accounting for 64.8% of all antidepressant prescriptions given. Higher doses of SSRIs — qualified by the number of defined daily doses (DDDs), the average amount of the usually prescribed dose of a drug — were associated with a higher risk for severe dementia, defined as a more pronounced decline in a patient’s MMSE score. An SSRI intake greater than one DDD was associated with an additional decline in cognition scoring of 0.42 points per year. The study also observed a greater risk of fractures and all-cause mortality in patients with dementia prescribed at least one SSRI on or after diagnosis. Faster rates of cognitive decline were observed in males taking antidepressants compared to females taking antidepressants. SNRIs were not associated with increased cognitive decline, but the authors caution that the study may have been underpowered.
The authors caution that the severity of dementia in individual patients could independently contribute to cognitive decline, making it difficult to definitively attribute the observed effects solely to antidepressant use. They add that future studies are needed to clarify the interactions between specific antidepressants and the rate of cognitive decline in patients with dementia.
