"Take results seriously": Study: Antidepressants could accelerate dementia

A new study warns of the dangers of certain antidepressants for dementia patients. These drugs could even accelerate mental decline and lead to an increased risk of bone fractures and mortality. Experts are calling on doctors to be more cautious.

According to a study, certain antidepressants can possibly accelerate mental decline in dementia patients. Whether they should really be prescribed must therefore be thoroughly examined for each patient, warns the research team in the specialist journal "BMC Medicine" . The drugs affected are so-called selective serotonin reuptake inhibitors (SSRIs). These are a group of drugs that are often used to treat depression because they increase the serotonin level in the brain. These include citalopram, sertraline and escitalopram.

"These results must be taken seriously," said Peter Berlit, Secretary General of the German Society of Neurology (DGN), who was not involved in the study. There had been similar indications before, especially for tricyclic antidepressants (TCAs), an older class of antidepressants that work differently than SSRIs and often have more side effects. They should therefore not be used in dementia patients. In any case, the use of such drugs in this group of patients is usually not sensible: "It has long been known that antidepressants have little to no effect on dementia patients."

Brain structures often damaged

The reason for this may be that the relevant brain structures in those affected are already damaged and can no longer be influenced by such active substances, explained Klaus Fließbach, senior physician at the University Hospital in Bonn. The mechanisms behind certain symptoms may also be completely different from those in people without dementia. For example, around half of patients with Alzheimer's disease are affected by apathy - but in these patients it is not a sign of depression. Against this background, it is not surprising that antidepressants do not work in such cases.

In general, depression and dementia are closely linked: a large proportion of dementia sufferers show symptoms that are also typical of depression, such as sleep disorders, reduced appetite, restlessness, aggressiveness or sad mood. Depressive disorders, in turn, can impair cognitive abilities.

Doctors currently assume that SSRI and so-called SNRI antidepressants - another group of antidepressants - have no harmful effects on dementia sufferers, said Fließbach, a neuroscientist at the German Center for Neurodegenerative Diseases (DZNE) in Bonn. They are used, for example, for restlessness, impaired impulse control or the aforementioned apathy.

Expert: More cautiously applied

Even at the onset of dementia, antidepressants are still frequently prescribed in Germany, explained Berlit. "Often by the family doctor, who does not initially recognize this as an early symptom of dementia." More caution when prescribing for older patients is certainly appropriate - especially in light of the new results: According to the DGN Secretary General, SSRI antidepressants are often used in older people.

As the researchers led by Sara Garcia-Ptacek from the Karolinska Institute in Solna themselves point out, the study has limitations and the results should be checked by further analyses. "The symptoms of depression themselves can contribute to the worsening of dementia," Berlit gave as an example. What proportion of the acceleration is due to this and what proportion to the antidepressants cannot be determined with the available data. "The results are extremely difficult to interpret," Fließbach also stressed. The study only shows a possible causal connection - it has not been proven with the data.

Dementia test shows deterioration

The analysis included almost 19,000 people with an average age of 78 who were newly diagnosed with dementia and had been prescribed antidepressants up to six months before the dementia diagnosis. The mental function of each patient was assessed using a dementia test that measures orientation and short-term memory.

During the follow-up period of about four years on average, 23 percent of patients received a new prescription for an antidepressant. The majority of these were SSRIs (65 percent of prescriptions). Higher SSRI doses were associated with a higher risk of severe dementia, defined as a greater deterioration in a patient's test scores. The deterioration was faster in men than in women.

More fractures and higher mortality

The study also provided evidence of a higher risk of bone fractures and higher mortality in the group of patients who were prescribed at least one SSRI antidepressant at or after their dementia diagnosis. The researchers suspect that further studies could also show similar connections for another group of antidepressants, the SNRIs.

Fließbach's conclusion is that these are interesting indications, but that they require further clarification. The results are another reason to be cautious when prescribing psychotropic drugs to older people. "It should be carefully checked whether there is really a need." This is always necessary because of the possible interactions with other medications. Seniors in particular often take a number of different medications - how these affect each other is often not yet known exactly.