Mood and behavior changes may show up years before MCI or dementia
Zhou Z et al., 2026, Alzheimer’s Research & Therapy (published Oct 28, early access)
doi:10.1186/s13195-026-02228-9
Secondary analysis of a longitudinal cohort (NACC), 11,781 cognitively normal adults aged 60+
Summary: Families often notice personality or mood changes before memory problems, and clinicians need to know how to weigh them. This study followed adults over 60 who started out cognitively normal. Of these, 2,865 developed MCI, and 731 of them went on to dementia. Neuropsychiatric symptoms were measured with the NPI-Q and mild behavioral impairment domains. People who developed MCI already differed in overall symptoms about 12 years before diagnosis (RR 1.42); before dementia, the difference became significant about 5 years out (RR 1.41). Emotional dysregulation separated the groups earliest. Links to brain pathology at autopsy were mixed across Alzheimer’s, Lewy body and vascular disease. Limitations: the 12-year estimate sits at the edge of the data window, and the authors say these are group patterns whose value for predicting an individual’s course hasn’t been validated.
Takeaways for clinicians:
New mood or behavior changes in late life can be one early signal among several. Specific symptom areas increased in a staggered way over the 5 to 1 years before dementia, so a recent change may matter differently from a lifelong trait.
The brain changes behind these symptoms varied (Alzheimer’s, Lewy body, and vascular disease); no single cause accounted for them.
These are population-level trajectories, not a validated individual predictor.
Takeaways for families:
Changes like irritability or low mood can sometimes come years before memory problems. They also often have other causes and don’t mean dementia is coming.
Trouble managing emotions was the earliest difference the researchers saw.
The data came from a research registry of US memory centers, which may not reflect everyone.
