NOT REMEMBERING DREAMS COULD BE AN EARLY SIGN OF ALZHEIMER’S, ACCORDING TO A STUDY LED BY CIEN

• A study led by the Centro de Investigación de Enfermedades Neurológicas (CIEN) identifies the lack of dream recall as a possible early indicator of the disease.
• The data come from the Vallecas Project, one of Europe’s leading long-term cognitive follow-up cohorts.
• The study opens up the possibility of using dream recall as an early indicator in Alzheimer’s diagnosis, complementing other established biomarkers.

Madrid, April 7, 2026. Not remembering dreams could be linked to the earliest brain changes associated with Alzheimer’s disease. This is highlighted by a recent international study published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, involving the Fundación Reina Sofía and CIEN (Centro de Investigación de Enfermedades Neurológicas), with data and analyses from the Vallecas Project, one of Europe’s leading cohorts for the study of cognitive aging.

The research, conducted on 1,049 cognitively healthy older adults, shows that those who do not recall their dreams more frequently present biomarkers associated with Alzheimer’s, such as elevated levels of tau protein in blood and the presence of the APOE ε4 gene, the main genetic risk factor for developing the disease.

An association independent of memory, with long-term impact

One of the most relevant aspects of the study is that this relationship holds independently of performance on memory tests, reinforcing its potential value as an early signal.

In addition, the results show that individuals who did not recall their dreams at the beginning of the study experienced faster cognitive decline and a higher likelihood of developing dementia during the follow-up period, which extended up to ten years.

The role of the Vallecas Project and clinical implications

The study is based on data from the Vallecas Project, led by CIEN and funded by the Fundación Reina Sofía. For more than a decade, it has followed a cohort of older adults without cognitive impairment (through cognitive testing, blood analyses, and MRI scans) with the aim of identifying early signs of the disease.

Researchers suggest that this relationship could be explained by alterations in the so-called default mode network, a brain system involved in generating dream content and known to be affected in the early stages of Alzheimer’s. In this sense, difficulty recalling dreams would not be due to memory problems, but rather to alterations in their content - an even earlier phenomenon.

“This study suggests that something as everyday as remembering dreams may be linked to very early brain processes associated with Alzheimer’s. It is not a diagnostic criterion, but it is a relevant clue to advance early detection, which is currently one of the key areas of research,” says Pascual Sánchez-Juan, Scientific Director of CIEN and senior author of the study.