Why nightmares could increase dementia risk and how to get better sleep

In the last years of her life, my mother began to have nightmares. One recurred from time to time and became a metaphor for the dementia that, in the end, took her life. In it, she was trapped on a ship and could not get off.

Once, while staying with my sister, mum began to crash around her room in the night. When my sister went to investigate, she found our mother trying to get off her ship. On another occasion, while with me, she clambered on top of the toilet, again to get off the ship. She fell backwards, cracking her head on the floor, and required stitches.

My mother’s nightmares could have been linked to Alzheimer’s disease, according to a 2024 study by a team at Boston University in the US state of Massachusetts. It found that cognitive impairment had a correlation with higher nightmare frequency and distress in the elderly.

However, Dr Abidemi Otaiku, a neuroscientist at Imperial College London, says that nightmares can be a marker of earlier dementia – and even a driver of it.

His findings have shown that frequent or persistent nightmares may be an easily identifiable marker of dementia risk, one that can be detected even in the first decade of life. Other risk factors for dementia, such as diabetes and hypertension, typically only surface from middle age, he says.