Sleep aids and dementia: Studies find both risks and benefits



Common sleep drugs linked to cognitive aging

Chris Fox, MD, a researcher at the University of East Anglia in Norwich, England, and his colleagues demonstrated in 2018 that long-term exposure to anticholinergic drugs, a class that includes some antidepressants and antihistamines used to promote sleep, was associated with a higher risk of dementia, while use of benzodiazepines, a class of sedatives used commonly in older people as sleep aids, was not. (Whether benzodiazepine exposure relates to dementia remains controversial.)

At AAIC 2019, Dr. Fox presented findings from a study of 337 brains in a U.K. brain bank, of which 17% and 21% came from users of benzodiazepines and anticholinergic drugs, whose usage history was well documented. Dr. Fox and his colleagues found that, while neither anticholinergic nor benzodiazepine exposure was associated with brain pathology specific to that seen in Alzheimer’s disease, both classes of drugs were associated with “slight signals in neuronal loss” in one brain region, the nucleus basalis of Meynert. Dr. Fox described the drugs as causing “an increase in cognitive aging” which could bear on Alzheimer’s risk without being directly causative.

Newer sleep drugs may help Alzheimer’s patients

Scientists working for drug manufacturers presented findings on agents to counter the circadian rhythm disturbances seen in people with Alzheimer’s disease. Margaret Moline, PhD, of Eisai in Woodcliff Lake, N.J., showed some results from a phase 2, dose-ranging, placebo-controlled study of the experimental agent lemborexant in 62 subjects aged 60-90 with mild to moderate Alzheimer’s disease and sleep disturbances. (Lemborexant, an orexin receptor agonist that acts to regulate wakefulness, is being investigated in a broad range of sleep disorders.) Patients were randomized to one of four doses of lemborexant or placebo and wore a device for sleep monitoring. Nighttime activity indicating arousal was significantly lower for people in two dosage arms, 5 mg and 10 mg, compared with placebo, and treatment groups saw trends toward less sleep fragmentation and higher total sleep time, Dr. Moline told the conference.

Suvorexant (Belsomra), the only orexin receptor antagonist currently licensed as a sleep aid, is also being tested in people with Alzheimer’s disease. At AAIC 2019, Joseph Herring, MD, PhD, of Merck in Kenilworth, N.J., presented results from a placebo-controlled trial of 277 patients with Alzheimer’s disease and insomnia, and reported that treatment with 10 or 20 mg of suvorexant over 4 weeks was associated with about an extra half hour of total nightly sleep, with a 73-minute mean increase from baseline, compared with 45 minutes for patients receiving placebo (95% CI, 11-45; P less than .005).

Trazodone linked to slower cognitive decline

An inexpensive antidepressant used in low doses as a sleep aid, including in people with Alzheimer’s disease, was associated with a delay in cognitive decline in older adults, according to results from a retrospective study. Elissaios Karageorgiou, MD, PhD, of the University of California, San Francisco, and the Neurological Institute of Athens presented results derived from two cohorts: patients enrolled at the UCSF Memory and Aging Center and women enrolled in the Study for Osteoporotic Fractures (SOF) in Women. The investigators were able to identify trazodone users in the studies (with two or more contiguous study visits reporting trazodone use) and match them with control patients from the same cohorts who did not use trazodone.

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