Mental Disorders Tied to Subsequent Dementia Onset

Associations consistent across different psychiatric conditions, for Alzheimer disease and all other dementias

WEDNESDAY, Feb. 23, 2022 (HealthDay News) — Mental disorders are associated with later onset of dementia, according to a study published online Feb. 16 in JAMA Psychiatry.

Leah S. Richmond-Rakerd, Ph.D., from the University of Michigan in Ann Arbor, and colleagues assessed whether mental disorders antedate dementia. The analysis included more than 1.7 million individuals identified through a population-based administrative register who resided in New Zealand between July 1988 and June 2018.

The researchers found that compared with individuals without a mental disorder, those with a mental disorder were at higher risk for developing subsequent dementia (relative risk [RR], 4.24; hazard ratio, 6.49). Those with a mental disorder who developed dementia did so a mean of 5.60 years earlier than those with dementia but without a mental disorder. Associations were similar across sex and age, and when adjusting for preexisting chronic physical diseases and socioeconomic deprivation. Associations persisted across mental disorders and self-harm behavior (RRs ranged from 2.93 for neurotic disorders to 6.20 for psychotic disorders) and were seen for both Alzheimer disease (RR, 2.76) and all other dementias (RR, 5.85).

“Ameliorating mental disorders in early life might also ameliorate neurodegenerative conditions and extend quality of life in old age,” the authors write.